Reference intervals of gestational sac, yolk sac and embryo volumes using three-dimensional ultrasound

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Reference intervals of gestational sac, yolk sac and embryo volumes using three-dimensional ultrasound"

Transcription

1 Ultrasound Obstet Gynecol 29; 34: Published online in Wiley InterScience ( DOI: 1.12/uog.7348 Reference intervals of gestational sac, yolk sac and embryo volumes using three-dimensional ultrasound J. S. BAGRATEE*, L. REGAN, V. KHULLAR, C. CONNOLLY and J. MOODLEY* *Department of Obstetrics and Gynaecology, Nelson R Mandela School of Medicine, University of Kwa-Zulu Natal and Medical Research Council, Durban, South Africa and Imperial College Academic Health Sciences Centre at St Mary s Hospital, London, UK KEYWORDS: crown rump length; embryo volume; first trimester; gestational sac diameter; gestational sac volume; reference intervals; three-dimensional ultrasound; yolk sac volume ABSTRACT Objectives To create reference intervals of gestational sac volume (GSV), yolk sac volume (YSV), embryo volume (EV), crown rump length (CRL) and gestational sac diameter (GSD) in the first trimester of pregnancy using three-dimensional ultrasound. Methods Women in the first trimester of pregnancy were invited to participate in the study. Inclusion criteria were well-established dates, and that the women were non-smokers and healthy, without any medical disorders. Three-dimensional ultrasound volumetric data (GSV, YSV, EV) were collected together with standard two-dimensional measurements of CRL and GSD. For each measurement separate regression models were fitted to estimate the mean and SD at each gestational age. The 5 th, 5 th and 95 th centiles were derived using a combination of these regression models. Results One hundred and sixty-six women at between 6 and 12 weeks gestation were scanned once. The mean (± SD) maternal age was 29.4 (± 5) years. There were no miscarriages and no congenital abnormalities were noted. Mean gestational age at delivery was 39.3 (± 1.4) weeks and mean birth weight was 3.3 (±.4) kg. The CRL centiles fitted a cubic model and the GSD centiles fitted a linear model. The centiles for YSV fitted a quadratic model on the modified log-transformed data. The centiles for GSV and EV were modeled using quantile regression. Conclusion Reference intervals and centile charts for first-trimester GSV, YSV and EV have been created in addition to CRL and GSD using rigorous methodology. Copyright 29 ISUOG. Published by John Wiley & Sons, Ltd. INTRODUCTION The ability to accurately determine the volumes of the gestational sac, yolk sac and the embryo enables the creation of gestational age-related centiles that may be used as the basis for predicting adverse pregnancy outcome. The use of three-dimensional (3D) ultrasonography has facilitated accurate volume estimation that has been confirmed in many organ systems, either in vitro or in vivo 1,2, and it has also been found to be superior to two-dimensional (2D) ultrasound volumetry 3. However, some researchers still use incorrect methodology to estimate gestational age-specific reference intervals for embryo measurements 4. It is recommended that data from each pregnancy are included once only, as cross-sectional data, in the development of reference intervals for fetal size 5. This has not been the case with published reference intervals for first-trimester volumetric measurements 6 8. Longitudinal studies may be used to produce reference intervals for fetal size and fetal growth 9, however, appropriate methodology has not always been employed 8. Figueras et al. 1 stated that they used appropriate methodology in constructing centile curves for yolk sac volume (YSV) and gestational sac volume (GSV), but these centiles were not presented in their paper. We therefore aimed to produce valid reference intervals for first-trimester GSV, YSV and embryo volume (EV) using 3D transvaginal ultrasonography. In addition, centiles of gestational sac diameter (GSD) and crown rump length (CRL) were constructed for the same reference population. The centiles of CRL were compared with previously published centiles 11, and the relationships between CRL and EV, and CRL and GSV were analyzed. METHODS This cross-sectional observational study was performed in the Early Pregnancy Assessment Unit at St Mary s Correspondence to: Prof. J. S. Bagratee, Department of Obstetrics and Gynaecology, Nelson R Mandela School of Medicine, Private Bag 7, Congella, 413, South Africa ( Accepted: 3 June 29 Copyright 29 ISUOG. Published by John Wiley & Sons, Ltd. ORIGINAL PAPER

2 54 Bagratee et al. Hospital, London, UK. The local research ethics committee approved the study. Letters were sent to local general practitioners inviting women with a positive pregnancy test to participate in this study in the first trimester of pregnancy. The women were informed that the study involved an ultrasound examination for confirmation of their pregnancy and 3D ultrasound to record the GSV, YSV and EV. Inclusion criteria were: healthy women without any medical disorders, non-smokers, a singleton pregnancy, regular menses without hormonal contraception for at least three cycles before conception and a precise date of their last menstrual period or known date of embryo transfer in assisted reproduction. The gestational age was calculated by the modified Naegele s rule. Last menstrual period-derived gestational age was compared with ultrasound-derived gestational age using CRL 12 and if there was a marked discrepancy of 2 weeks or more then the woman was excluded from the study. In addition, those women with uncertain dates or early pregnancy loss were also excluded from the study. Informed consent was obtained from all participants. The study was performed with a 7.5-MHz transvaginal probe using a Combison 53D ultrasound machine (Kretztechnik AG, Zipf, Austria). Initially, using conventional 2D transvaginal ultrasound imaging, the CRL and GSD were each recorded. The CRL was recorded as an average of three measurements, which were obtained from separate printed images to prevent the examiner seeing the results of the previous measurement and preventing the introduction of bias in subsequent measurements. The 2D measurements of the gestational sac included the maximum transverse diameter (D1) in the transverse plane and the maximum anteroposterior and longitudinal diameters (D2 and D3) in the sagittal plane. The average of the three measurements was recorded as the GSD. The gestational sac was visualized again in the sagittal plane and the region of interest was selected using the volume box. The patient was then asked to hold her breath and, with the vaginal probe held stationary, the volume data were generated by the automatic rotation of the transducer crystal through 18 for 5 2 s. The scanned region was displayed on the screen in the three orthogonal planes (transverse, sagittal and coronal) after volume acquisition, and the examiner confirmed that the entire gestational sac was contained in the acquired volume scan. All scans were performed by a single examiner (J. S. B.). The volume scans were stored on 54 MB 1.3 GB Philips or Sony hard discs with an integrated magneto-optical drive for later measurement and analysis. Determination of GSV, YSV and EV was performed by sequentially viewing and tracing each structure in one of the three orthogonal planes at 1 2 mm intervals using the contour mode. During this procedure the gestational sac was magnified on the screen as much as possible to minimize measurement error. The computer software automatically calculated the volume from the measured circumferences and distances between them. Intra- and interobserver reliability of measurement of GSV, YSV and EV was tested on a random selection of 15 pregnancies of between 6 and 12 weeks gestation. Each observer (J. S. B. and V. K.) performed two measurements of GSV, YSV and EV on separate occasions using the stored volume and were unaware of each other s results until completion of the study. AllthewomenwerereferredtotheStMary santenatal clinic and the antenatal and labor data were recorded postdelivery. Statistical analysis Statistical analysis was performed using STATA version 9 (StataCorp, College Station, TX, USA). The gestational age-related reference intervals were obtained using the recommendations of Royston and Wright 4. Least-squares regression analysis was used to determine the mean curves as polynomial functions of exact gestational age measured in days. A number of different models were explored for each measurement. The selection of the final model depended on the appearance of the curve and its goodness of fit, particularly at the tails of the distribution. Another important criterion was the simplicity of the model. As recommended by Royston and Wright 4, a cubic polynomial was initially fitted to the data. If the cubic coefficient was not significantly different from zero, a quadratic polynomial was used and the quadratic coefficient assessed. This process was repeated until all the coefficients in the model were significantly different from zero. Very small coefficients that contributed little to the model were dropped in favor of simpler models. Fitted values from the most appropriate polynomial regression curve of the desired measurement were used to predict the mean for each gestational age. Similarly, in determining the curves for the SD, a polynomial or linear model was selected depending on the most appropriate fit for the scaled absolute residuals plotted against gestational age. The appearance of the model with its mean and SD curves was checked by examining the scatter patterns of points (SD scores) relative to ± The normality of the SD score was assessed using the Shapiro Wilk W-test and a normal plot. Once the final model had been determined, the 5 th,5 th and 95 th centiles were calculated by substituting the expressions for the mean and SD into the equation: centile = mean + (K SD), where K = 1.645,, Tables were then prepared for the 5 th,5 th and 95 th centiles and a scatter plot with reference intervals was generated. Where negative centile values were obtained for early gestational age, the model-fitting process was repeated using a cubic polynomial of a logarithmic transformation of the measurement. If none of the models met the required criteria, the same process was repeated using a modified (shifted) logarithmic transformation of the measurement (log(x) + m). The Shapiro Wilk W-test was used to determine the most appropriate value of m. When all refinements of the model failed to produce Copyright 29 ISUOG. Published by John Wiley & Sons, Ltd. Ultrasound Obstet Gynecol 29; 34:

3 First-trimester reference intervals using three-dimensional ultrasound 55 centiles meeting the required criteria, quantile regression was used to determine more appropriate centiles 13. The quantile regression model was assessed using three criteria 13 : no negative values; that 1% of observed values lay above the 9 th centile and below the 1 th centile; and that these values were scattered randomly across the gestational age range. The quantile regression equations were used to calculate the 5 th,5 th and 95 th centiles and a scatter plot with reference intervals was constructed. Intraobserver variation was calculated as the difference between the first and second measurements by one observer. Interobserver variation was calculated using the mean measurement for each observer. The mean difference and SD are reported. The intra- and interobserver variation were also expressed as the intraclass correlation coefficient (ICC). A random effects model was used to estimate the ICC for consistency. Inter- and intraobserver agreement were assessed following the methods described by Bland and Altman 14. RESULTS One hundred and seventy-five healthy pregnant women at between 6 and 12 weeks gestation responded to our letter of invitation for a first-trimester ultrasound scan at the Early Pregnancy Assessment Unit. Nine women were excluded from the study following their ultrasound examination: two had an anembryonic pregnancy, two had early embryonic demise and five women had incorrect dates. The menstrual dates (ultrasound CRL dates in brackets) of these five women were: 7 + 1(9+ ), (12 + 1), (14+ 1), (13+ 2) and (14 + 5) weeks. One hundred and sixty-six women at between 6 and 12 weeks gestation who met the eligibility criteria were enrolled and completed the study. None of these women sustained a miscarriage or stillbirth and no infants had any congenital abnormalities. The mean age (± SD) of the women was 29.4 (±5) years, mean gestational age at delivery was 39.3 (±1.4) weeks and the mean birth weight was 3.3 (±.4) kg. Ninety-nine women (59.6%) were nulliparous and 67 women (4.4%) were parous (range, para 1 to para 4). Details of the reference equations derived are given below. Medians and 5 th and 95 th centiles for each measurement by weeks of gestational age are shown in Table 1. Scatter plots of each measurement against gestational age, with the modeled centiles, are presented in Figure 1. Crown rump length A least squares cubic model was shown to be the best model for the reference intervals of CRL in relation to gestational age (GA): CRL = (.33 GA 3 ). For the SD, a linear model showed the most appropriate fit: SD CRL = (.67 GA). A normal probability plot of the Z-scores showed the scores lying close to a straight line. The Shapiro Wilk W-test was not significant (P =.6), thus the assumption of normality could not be rejected. In addition, the Z-scores were randomly scattered around zero. The numbers observed above the 9 th centile, 13 (7.8%), and below the 1 th centile, 15 (9.%), were close to the expected value of 1%. Centiles by days of gestation are provided in Table S1. Figure 2 and Table S2 present a comparison of our reference curve for median CRL with that published by Robinson and Fleming 11. The mean difference in CRL across the gestational age range studied was.14 (range, 1.24 to 3.84). Gestational sac diameter A linear model provided the best fit to the GSD data in relation to GA: GSD = (7.385 GA). For the SD, a linear model also showed the most appropriate fit: SD GSD = (.537 GA). A normal probability plot of the Z-scores showed the scores lying close to a straight line. The Shapiro Wilk W- test was not significant (P =.5), thus the assumption of normality could not be rejected. In addition, the Z-scores were randomly scattered around zero. In this case 13 (7.8%) points were below the 1 th centile and 15 points (9.%) were above it. Gestational sac volume The best model for GSV was a modified logarithmic transformation of the form log (GSV + 9). A linear function provided a good fit to the transformed values: log (GSV + 9) =.17 + (.362 GA). When the predicted values were back-transformed to calculate the centiles, we obtained a negative value of.6 forthe5 th centile at 6 weeks. Quantile regression was then used to estimate more appropriate centiles. The quantile regression models that best fit the data are: 5 th Centile : log (GSV) = (.675 GA); 5 th Centile : log (GSV) = (.545 GA); 95 th Centile : log (GSV) =.171 (.411 GA). The model fitted satisfactorily as 17 observations (1.2%) fell below the 1 th centile and 18 (1.8%) fell above the 9 th percentile. The data points lying outside the reference interval were spread throughout the range. Copyright 29 ISUOG. Published by John Wiley & Sons, Ltd. Ultrasound Obstet Gynecol 29; 34:

4 56 Bagratee et al. Table 1 Calculated 5 th, 5 th and 95 th centiles for crown rump length (CRL), gestational sac diameter (GSD), gestational sac volume (GSV), yolk sac volume (YSV) and embryo volume (EV) according to gestational age (GA) GSD (mm) GSV (mm 3 ) YSV (mm 3 ) EV (mm 3 ) GA* (weeks) n 5 th 5 th 95 th SD 5 th 5 th 95 th SD 5 th 5 th 95 th 5 th 5 th 95 th SD 5 th 5 th 95 th n represents the number of pregnancies included in the study at each week of GA. Measurements of YSV were not obtained for all pregnancies, with 25 at 1 weeks, 13 at 11 weeks and 9 at 12 weeks. *Centile and SD values are given for the midpoint of each gestational week. Yolk sac volume Measurements were available in 145 of the 166 pregnancies. A modified log transformation, log (YSV +.5), was used to model the data. A quadratic model provided the best fit: log (YSV +.5) = (.749 GA) (.34 GA 2 ). For the SD, a linear model showed the most appropriate fit: SD YSV =.78 + (.19 GA). A normal probability plot of the Z-scores showed them lying close to a straight line. The Shapiro Wilk W-test was not significant (P =.14), thus the assumption of normality could not be rejected. In addition, the Z-scores were randomly scattered around zero. The model fitted satisfactorily as 18 observations (12.4%) fell below the 1 th centile and 15 (1.3%) lay above the 9 th centile. The data points lying outside the reference interval were spread throughout the range. Embryo volume The best model for EV was a modified logarithmic transformation of the form log (EV +.15). A linear function provided a good fit to the transformed values: log (EV +.15) = (.85 GA). When the predicted values were back-transformed to calculate the centiles, we obtained a negative value of.49 for the 5 th centile at 6 weeks. Quantile regression was then used to estimate more appropriate centiles: 5 th Centile : log (EV) = (2.46 GA) (.41 GA 3 ); 5 th Centile : log (EV) = (3.116 GA) (.195 GA 2 ); 95 th Centile : log (EV) = (2.48 GA) (.842 GA 2 ). The model fitted satisfactorily as 15 observations (9.%) were below the 1 th centile and 15 (9.%) were above the 9 th centile. The data points lying outside the reference interval were spread throughout the range. Table 2 presents the intra- and interobserver variation of the 3D volume measurements. The volume measurements of GSV, YSV and EV showed high levels of intraand interobserver agreement. Table 3 shows the CRL and EV in relation to fetal gender. There was no difference in gestational age between the males and females (P =.4). Therefore overall measurement means and SDs are reported. There Copyright 29 ISUOG. Published by John Wiley & Sons, Ltd. Ultrasound Obstet Gynecol 29; 34:

5 First-trimester reference intervals using three-dimensional ultrasound 57 (a) 8 (b) 8 (c) GSD (mm) GSV (mm 3 ) (d).4 (e) 3 YSV (mm 3 ) EV (mm 3 ) Figure 1 Scatter plots with 5 th, 5 th and 95 th centiles of crown rump length (CRL) (a), gestational sac diameter (GSD) (b), gestational sac volume (GSV) (c), yolk sac volume (YSV) (d) and embryo volume (EV) (e) against gestational age Figure 2 Comparison of the reference curve for median crown rump length (CRL) against gestational age obtained in the present study ( ) with that published by Robinson and Fleming 11 ( ). were no statistical differences between males and females in CRL (P =.2) or in EV (P =.2). There was a very strong correlation (r =.94) between CRL and EV (Figure 3a). For CRL measurements between 2 and 7 mm the relationship was linear. There was also a very strong correlation (r =.95) between CRL and GSV (Figure 3b). DISCUSSION To the best of our knowledge, this is the first study in the literature that has used 3D transvaginal ultrasound to derive reference intervals of first-trimester GSV, YSV and EV using accepted methodology; the currently available reference intervals for these parameters are based on incorrect methodology 6 8. The use Table 2 Intra- and interobserver variation of three-dimensional volume measurements of gestational sac volume (GSV), yolk sac volume (YSV) and embryo volume (EV) Parameter Mean SD Range ICC Interobserver difference GSV (mm 3 ) ( 2.6 to.63).99 YSV (mm 3 ).4.1 (.9 to.3).97 EV (mm 3 ) (.12 to.8).99 Intraobserver difference GSV (mm 3 ) ( 3.6 to 1.17).99 YSV (mm 3 ).2.1 (.24 to.15).98 EV (mm 3 ) (.12 to.36).99 ICC, intraclass correlation coefficient. Table 3 Crown rump length (CRL) and embryo volume (EV) according to fetal gender Male Female Parameter n Mean SD n Mean SD P EV (mm 3 ) of appropriate methodology is crucial, as inaccurate centiles may lead to incorrect decisions regarding embryonic/fetal development, resulting in substandard clinical care 15. In the collection of data specifically for the purpose of developing centiles for size, Altman and Chitty 5 recommend that each fetus be included once only in the study. This was not the case with recently published reference intervals of first-trimester volumetric Copyright 29 ISUOG. Published by John Wiley & Sons, Ltd. Ultrasound Obstet Gynecol 29; 34:

6 58 Bagratee et al. (a) 3 EV (mm 3 ) GSV (mm 3 ) 2 1 (b) Figure 3 Embryo volume (EV) (a) and gestational sac volume (GSV) (b) plotted against crown rump length (CRL). measurements 6 8. Babinski et al. 6 created nomograms using 73 measurements obtained from 49 pregnancies between the 25 th and 65 th days post-ovulation. Although they recorded values from weeks of gestational age, they developed their reference intervals from weeks to weeks 6. Gadelha et al. 7 only studied a total of 25 fetuses in a longitudinal prospective study and measured each fetus on four occasions, during the 8 th,9 th,1 th and 11 th weeks of pregnancy. In our study, the gestational age was recorded precisely to the day, rather than rounding it off to the number of completed weeks. This impacts on the creation of the reference intervals, resulting in the mean and SD not changing smoothly with gestational age as one would expect on a biological basis 4. In our study the mean and SD were modeled using the exact gestational age, resulting in smooth reference interval curves. Gadelha et al. 7,using 3D ultrasound, and Weissman et al. 16, using 2D ultrasound, did not take this into account and presented their data rounded to each gestational week in the development of their centile charts. In the construction of reference intervals requiring a 9% range between the 5 th and 95 th centiles of the distribution, a sample size of 2 per week is recommended 17. The volumetric assessment by Aviram et al. 8 is limited as they studied between 1 and 14 fetuses per week from 6 to 11 weeks and only three fetuses at 12 weeks. In addition, their reference intervals were not obtained from a pregnant population with normal fetal outcome, as all 72 women recruited to their study underwent a termination of pregnancy. In the present study, we were able to recruit an adequate number of women between the 6 th and 12 th gestational weeks. This was, however, not possible for the fifth week of pregnancy, possibly owing to the fact that many women have a home pregnancy test when their menses are delayed by a week and only see their doctor in most instances after the 5 th week, or will call the practice nurse during their 5 th week of amenorrhea. It would have been only then that their general practitioner or practice nurse would have offered them the opportunity to contact one of the authors (J. S. B.) to have a pregnancy confirmation scan and additionally to determine the volume of the early pregnancy structures. Prior to the construction of the volume reference intervals, we developed reference intervals for CRL for this group of healthy women with a normal pregnancy outcome. We averaged the CRL obtained from three different satisfactory measurements because a single measurement may estimate gestational age with an SD of ±4.7 days, whereas an average of three different measurements may reduce the SD to ±2.7 days 11. Our values for CRL fitted a standard Gaussian distribution, confirmed by the plot of Z-scores against gestational age, and were similar to the reported normal values 11.BlandandAltmanhave argued that averaging repeated measurements for each subject may lead to narrower centiles at any given gestational age than had they been constructed from single measurements 18. Reference intervals derived from single CRL measurements may give widened centiles because they include a greater amount of measurement error. However, the impact is probably minimal in clinical practice. It has been reported previously that a sex difference in CRL was demonstrated from 8 weeks onward, with male embryos having an average measurement 2 mm greater than female embryos at the same gestational age 19. However, we found no difference in CRL or in EV between male and female embryos. Our formula for median GSV gives values that increase from 4.4 mm 3 at 6 weeks to mm 3 at 12 weeks. Our estimation of the GSV differs from the first reported reference intervals in the literature 2. Robinson 2 performed measurements using 2D ultrasound imaging and used the mathematical formula of a sphere to calculate volumes. He also used transabdominal ultrasound with a full bladder, in contrast to our measurements, which were performed transvaginally using a 7.5-MHz probe. Robinson 2 found that the mean GSV increased exponentially from 1 mm 3 at 6weeksto31mm 3 at 1 weeks and then in a more linear manner to 1 mm 3 at 13 weeks. He also found that the two-sds limits increased considerably with gestational age and concluded that volume measurements would allow a prediction of gestational age of no better than ±9 days, and were therefore of lesser value than CRL in measuring gestational age. In our study GSV increased in an exponential manner between 6 and 12 weeks gestation. Copyright 29 ISUOG. Published by John Wiley & Sons, Ltd. Ultrasound Obstet Gynecol 29; 34:

7 First-trimester reference intervals using three-dimensional ultrasound 59 In estimating GSV, we included the amniotic fluid, the extraembryonic celom and the fetus, as did Robinson 2. We found that the embryo occupied.9% of the GSV at 6 weeks and 16.8% at 12 weeks. In 3 pregnancies in the first trimester Weissman et al. 16, using 2D ultrasound measurements and the formula of an ellipsoid (V = 4/3 π r 1 r 2 r 3 ), found that the embryo occupied between 5 and 16% of the sac volume, and in their subsequent analysis of 95 pregnancies they therefore ignored the estimated EV when calculating the amniotic fluid volume. We obtained YSV in 145 of the 166 pregnancies in our study. The yolk sac is seen in all pregnancies from 5 weeks gestation onwards, when the gestational sac exceeds 11 mm in diameter 21. Its diameter increases in size up to 11 weeks and then decreases 22. The decreased vascularity of the yolk sac at the time of its maximum volume is proposed as the cause of its degeneration and disappearance 23. In our study, the reference intervals for first-trimester YSV increased in a linear fashion up to 1 weeks, then maintained a plateau until 11 weeks and decreased thereafter, similar to the findings of Kupesic et al. 23. In conclusion, we have presented new reference intervals for the volumes of the gestational sac, yolk sac and embryo in the first trimester of pregnancy using 3D ultrasound. Our approach has followed a rigorous methodology as prescribed by previous authors 4,5,15. ACKNOWLEDGMENTS We would like to thank the nursing and medical staff of the Early Pregnancy Assessment Unit at St Mary s Hospital, London, UK for their co-operation and assistance during the study. REFERENCES 1. King DL, King DL Jr, Shao MYC. Evaluation of in vitro measurement accuracy of a three-dimensional ultrasound scanner. J Ultrasound Med 1991; 1: Riccabona M, Nelson TR, Pretorius DH. Three dimensional ultrasound: accuracy of distance and volume measurements. Ultrasound Obstet Gynecol 1996; 7: Müller T, Sütterlin M, Pöhls U, Dietl J. Transvaginal volumetry of first trimester gestational sac: a comparison of conventional with three-dimensional ultrasound. J Perinatal Med 2; 28: Royston P, Wright EM. How to construct normal ranges for fetal variables. Ultrasound Obstet Gynecol 1998; 11: Altman DG, Chitty LS. Charts of fetal size: 1. Methodology. Br J Obstet Gynaecol 1994; 11: Babinski A, Nyari T, Jordan S, Nasseri A, Mukherjee T, Copperman AB. Three-dimensional measurement of gestational and yolk sac volumes as predictors of pregnancy outcome in the first trimester. Am J Perinat 21; 18: Gadelha PS, Da Costa AG, Filho FM, El Beitune P. Amniotic fluid volumetry by three-dimensional ultrasonography during the first trimester of pregnancy. Ultrasound Med Biol 26; 32: Aviram R, Kamar Shpan D, Markovitch O, Fishman A, Tepper R. Three-dimensional first trimester fetal volumetry: comparison with crown rump length. Early Hum Dev 24; 8: Royston P, Altman DG. Design and analysis of longitudinal studies of fetal size. Ultrasound Obstet Gynecol 1995; 6: Figueras F, Torrents M, Munoz A, Comas C, Antolin E, Echevarria M, Carrera JM. Three-dimensional yolk and gestational sac volume. A prospective study of prognostic value. J Reprod Med 23; 48: Robinson HP, Fleming JEE. A critical evaluation of sonar crown-rump length measurements. Br J Obstet Gynaecol 1975; 82: Hadlock FP, Shah YP, Kanon DJ, Math B, Lindsay JV. Fetal crown rump length: Reevaluation of relation to menstrual age (5 18 weeks) with high-resolution real-time US. Radiology 1992; 182: Gannoun A, Girard S, Guinot C, Saracco J. Reference curves based on non-parametric quantile regression. Statist Med 22; 21: Bland JM, Altman DG. Measurement agreement in method comparison studies. Stat Meth Med Res 1999; 8: Silverwood RJ, Cole TJ. Statistical methods for constructing gestational age-related reference intervals and centile charts for fetal size. Ultrasound Obstet Gynecol 27; 29: Weissman A, Itskovitz-Eldor J, Jakobi P. Sonographic measurement of amniotic fluid volume in the first trimester of pregnancy. J Ultrasound Med 1996; 15: Royston P. Constructing time-specific reference ranges. Stat Med 1991; 1: Bland JM, Altman DG. Agreement between methods of measurement with multiple observations per individual. J Biopharm Stat 27; 17: Pedersen JF. Ultrasound evidence of sexual difference in fetal size in first trimester. Br Med J 198; 281: Robinson HP. Gestational sac volumes as determined by sonar in the first trimester of pregnancy. BrJObstetGynaecol 1975; 82: Bree RL, Marn CS. Transvaginal sonography in the first trimester: embryology, anatomy and hcg correlation. Semin Ultrasound CT MR 199; 11: Jauniaux E, Jurkovic D, Henriet Y, Rodesch F, Hustin J. Development of the secondary human yolk sac. Correlation of sonographic and anatomical features. Hum Reprod 1991; 6: Kupesic S, Kurjak A, Ivancic-Kosuta M. Volume and vascularity of the yolk sac studied by three-dimensional ultrasound and color Doppler. J Perinat Med 1999; 27: SUPPORTING INFORMATION ON THE INTERNET The following supporting information may be found in the online version of this article: Table S1 Mean and standard deviation of crown rump length for each day of menstrual age from 6 12 weeks Table S2 Comparison of our formula for mean crown rump length against that published by Robinson and Fleming 11 Copyright 29 ISUOG. Published by John Wiley & Sons, Ltd. Ultrasound Obstet Gynecol 29; 34:

Charts of fetal size: limb bones

Charts of fetal size: limb bones BJOG: an International Journal of Obstetrics and Gynaecology August 2002, Vol. 109, pp. 919 929 Charts of fetal size: limb bones Lyn S. Chitty a, *, Douglas G. Altman b Objective To construct new size

More information

Fetal size and dating: charts recommended for clinical obstetric practice

Fetal size and dating: charts recommended for clinical obstetric practice Fetal size and dating: charts recommended for clinical obstetric practice Pam Loughna 1, Lyn Chitty 2, Tony Evans 3 & Trish Chudleigh 4 1 Academic Division of Obstetrics and Gynaecology, Nottingham University

More information

Reference Ranges for the Fetal Cardiac Circumference Derived by Cardio Spatiotemporal Image Correlation From 14 to 40 Weeks Gestation

Reference Ranges for the Fetal Cardiac Circumference Derived by Cardio Spatiotemporal Image Correlation From 14 to 40 Weeks Gestation ORIGINAL RESEARCH Reference Ranges for the Fetal Cardiac Circumference Derived by Cardio Spatiotemporal Image Correlation From 14 to 40 Weeks Gestation Kuntharee Traisrisilp, MD, Fuanglada Tongprasert,

More information

Fetal growth assessment at wks of gestation based on a population anomaly screening program in central-eastern Poland

Fetal growth assessment at wks of gestation based on a population anomaly screening program in central-eastern Poland Archives of Perinatal Medicine 19(4), 191-199, 2013 ORIGINAL PAPER Fetal growth assessment at 11-14 wks of gestation based on a population anomaly screening program in central-eastern Poland IZABELA WNUCZEK-MAZUREK

More information

Distribution of nuchal translucency in antenatal screening for Down s syndrome. JPBestwick,WJHuttlyandNJWald... METHODS

Distribution of nuchal translucency in antenatal screening for Down s syndrome. JPBestwick,WJHuttlyandNJWald... METHODS 8 ORIGINAL ARTICLE Distribution of nuchal translucency in antenatal screening for JPBestwick,WJHuttlyandNJWald... J Med Screen 2010;17:8 12 DOI: 10.1258/jms.2010.009107 See end of article for authors affiliations...

More information

Comparison of nuchal translucency measurements obtained using Volume NT TM and two- and three-dimensional ultrasound

Comparison of nuchal translucency measurements obtained using Volume NT TM and two- and three-dimensional ultrasound Ultrasound Obstet Gynecol 2012; 39: 175 180 Published online 5 January 2012 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/uog.8996 Comparison of nuchal translucency measurements obtained

More information

What is the diagnostic value of ultrasound for determining a viable intrauterine pregnancy?

What is the diagnostic value of ultrasound for determining a viable intrauterine pregnancy? What is the diagnostic value of ultrasound for determining a viable intrauterine pregnancy? Full citation Sample size Tests Methods Results Limitations Steinkampf,M.P., Guzick,D.S., Hammond,K.R., Blackwell,R.E.,

More information

Standardization of three-dimensional images in obstetrics and gynecology: consensus statement

Standardization of three-dimensional images in obstetrics and gynecology: consensus statement Ultrasound Obstet Gynecol 2007; 29: 697 703 Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.4009 Standardization of three-dimensional images in obstetrics and gynecology:

More information

How do I analyse observer variation studies?

How do I analyse observer variation studies? How do I analyse observer variation studies? This is based on work done for a long term project by Doug Altman and Martin Bland. I recommend that you first read our three Statistics Notes on measurement

More information

Prognosis of Very Large First-Trimester Hematomas

Prognosis of Very Large First-Trimester Hematomas Case Series Prognosis of Very Large First-Trimester Hematomas Juliana Leite, MD, Pamela Ross, RDMS, RDCS, A. Cristina Rossi, MD, Philippe Jeanty, MD, PhD Objective. The aim of this study was to evaluate

More information

Intrauterine sonographic assessments of embryonic heart diameter

Intrauterine sonographic assessments of embryonic heart diameter Human Reproduction vol.12 no.10 pp.2286 2291, 1997 Intrauterine sonographic assessments of embryonic heart diameter Toshiyuki Hata 1, Daisaku Senoh, Kohkichi Hata and Kohji Miyazaki Department of Obstetrics

More information

Fetal Biometry. Updated 10/29/2008. Jimmie Wong, MD Assistant Professor of Radiology David Geffen School of Medicine at UCLA

Fetal Biometry. Updated 10/29/2008. Jimmie Wong, MD Assistant Professor of Radiology David Geffen School of Medicine at UCLA Updated 10/29/2008 Jimmie Wong, MD Assistant Professor of Radiology David Geffen School of Medicine at UCLA -Terminology -Gestational age (GA) -Refers to the length of pregnancy counting from the LMP and

More information

A. Evidence for an individually adjustable standard to assess birth weight:

A. Evidence for an individually adjustable standard to assess birth weight: Customised antenatal growth charts are designed to facilitate better supervision of fetal growth. The chart is printed out in early pregnancy, after confirmation of pregnancy dates, and allows serial plotting

More information

Estimation of Fetal Weight: Mean Value from Multiple Formulas

Estimation of Fetal Weight: Mean Value from Multiple Formulas Estimation of Fetal Weight: Mean Value from Multiple Formulas Michael G. Pinette, MD, Yuqun Pan, MD, Sheila G. Pinette, RPA-C, Jacquelyn Blackstone, DO, John Garrett, Angelina Cartin Mean fetal weight

More information

REPRODUCTIVE ENDOCRINOLOGY

REPRODUCTIVE ENDOCRINOLOGY FERTILITY AND STERILITY VOL. 82, NO. 5, NOVEMBER 2004 Copyright 2004 American Society for Reproductive Medicine Published by Elsevier Inc. Printed on acid-free paper in U.S.A. REPRODUCTIVE ENDOCRINOLOGY

More information

A practical approach to Bland-Altman plots and variation coefficients for log transformed variables

A practical approach to Bland-Altman plots and variation coefficients for log transformed variables 5 A practical approach to Bland-Altman plots and variation coefficients for log transformed variables A.M. Euser F.W. Dekker S. le Cessie J Clin Epidemiol 2008; 61: 978-982 Chapter 5 Abstract Objective

More information

Clinical Significance of First Trimester Umbilical Cord Cysts

Clinical Significance of First Trimester Umbilical Cord Cysts Clinical Significance of First Trimester Umbilical Cord Cysts Waldo Sepulveda, MD, Sergio Leible, MD, Angel Ulloa, MD, Milenko Ivankovic, MD, Carlos Schnapp, MD A cystic mass of the umbilical cord was

More information

Frontomaxillary and mandibulomaxillary facial angles at 11 + 0to13+ 6 weeks in fetuses with trisomy 18

Frontomaxillary and mandibulomaxillary facial angles at 11 + 0to13+ 6 weeks in fetuses with trisomy 18 Ultrasound Obstet Gynecol 2007; 30: 928 933 Published online 1 November 2007 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.2/uog.5188 Frontomaxillary and mandibulomaxillary facial angles

More information

Risk Calculation Software Requirements for Down's Syndrome Screening

Risk Calculation Software Requirements for Down's Syndrome Screening Screening Programmes Fetal Anomaly Risk Calculation Software Requirements for Down's Syndrome Screening Version 1 January 2013 Created by: Dave Wright, Barry Nix, Steve Turner, David Worthington and Andy

More information

Sonographic Accuracy of Estimated Fetal Weight in Twins

Sonographic Accuracy of Estimated Fetal Weight in Twins ORIGINAL RESEARCH Sonographic Accuracy of Estimated Fetal Weight in Twins Lorie M. Harper, MD, MSCI, Kimberly A. Roehl, MPH, Methodius G. Tuuli, MD, MPH, Anthony O. Odibo, MD, MSCE, Alison G. Cahill, MD,

More information

Nasal bone assessment in fetuses with trisomy 21 at 16 24 weeks of gestation by three-dimensional ultrasound

Nasal bone assessment in fetuses with trisomy 21 at 16 24 weeks of gestation by three-dimensional ultrasound DOI: 10.1002/pd.2938 ORIGINAL ARTICLE Nasal bone assessment in fetuses with trisomy 21 at 16 24 weeks of gestation by three-dimensional ultrasound Nicola Persico 1,2 *, Francisca Molina 3, Guillermo Azumendi

More information

Clinical Significance of Placenta Previa Detected at Early Routine Transvaginal Scan

Clinical Significance of Placenta Previa Detected at Early Routine Transvaginal Scan Clinical Significance of Placenta Previa Detected at Early Routine Transvaginal Scan Paolo Rosati, MD, Lorenzo Guariglia, MD Transvaginal ultrasonography in early pregnancy was used to determine the prevalence

More information

Ultrasonography of the Fetal Thyroid

Ultrasonography of the Fetal Thyroid Article Ultrasonography of the Fetal Thyroid Nomograms Based on Biparietal Diameter and Gestational Age Angela C. Ranzini, MD, Cande V. Ananth, PhD, MPH, John C. Smulian, MD, MPH, Michelle Kung, Anita

More information

Assessment of Fetal Growth

Assessment of Fetal Growth Assessment of Fetal Growth Unit / Trust: 1. INTRODUCTION The aim of this guideline template is to outline the methods used to assess fetal growth and the referral pathways utilising customised antenatal

More information

Myometrial Thickness in Pregnancy: Longitudinal Sonographic Study

Myometrial Thickness in Pregnancy: Longitudinal Sonographic Study Myometrial Thickness in Pregnancy: Longitudinal Sonographic Study Shimon Degani, MD, Zvi Leibovitz, MD, Israel Shapiro, MD, Ron Gonen, MD, Gonen Ohel, MD The purpose of this study was to evaluate in vivo

More information

Inferential Statistics

Inferential Statistics Inferential Statistics Sampling and the normal distribution Z-scores Confidence levels and intervals Hypothesis testing Commonly used statistical methods Inferential Statistics Descriptive statistics are

More information

Long-Term Prognosis of Pregnancies Complicated by Slow Embryonic Heart Rates in the Early First Trimester

Long-Term Prognosis of Pregnancies Complicated by Slow Embryonic Heart Rates in the Early First Trimester Long-Term Prognosis of Pregnancies Complicated by Slow Embryonic Heart Rates in the Early First Trimester Peter M. Doubilet, MD, PhD, Carol B. Benson, MD, Jeanne S. Chow, MD Slow embryonic heart rates

More information

International Fetal and Newborn Growth Standards for the 21 st Century

International Fetal and Newborn Growth Standards for the 21 st Century INTERBIO-21 st International Fetal and Newborn Growth Standards for the 21 st Century INTERBIO-21 st Update to the INTERGROWTH-21 st Ultrasound Manual 1 The International Fetal and Newborn Growth Consortium

More information

First trimester screening for Down syndrome using free β hcg, total hcg and PAPP-A: an exploratory study

First trimester screening for Down syndrome using free β hcg, total hcg and PAPP-A: an exploratory study PRENATAL DIAGNOSIS Prenat Diagn 2007; 27: 1118 1122. Published online 25 October 2007 in Wiley InterScience (www.interscience.wiley.com).1844 First trimester screening for Down syndrome using free β hcg,

More information

Ultrasound 101. Objectives. Second Trimester Ultrasound. Principles of Ultrasound. How sounds travels: Interfaces. How Ultrasound Works 10/4/2012

Ultrasound 101. Objectives. Second Trimester Ultrasound. Principles of Ultrasound. How sounds travels: Interfaces. How Ultrasound Works 10/4/2012 Ultrasound 101 Matthew Reeves, MD, MPH Mary Fjerstad, NP, MHS September 20, 2012 Objectives Understand basis physics of ultrasound How to apply principles Assessment of early pregnancy Gestational age

More information

Eastern Mediterranean Health Journal, Vol. 10, No. 3, 2004 437

Eastern Mediterranean Health Journal, Vol. 10, No. 3, 2004 437 Eastern Mediterranean Health Journal, Vol. 10, No. 3, 2004 437 Report Normal uterine size in women of reproductive age in northern Islamic Republic of Iran S. Esmaelzadeh, 1 N. Rezaei 1 and M. HajiAhmadi

More information

Sonographic screening for trisomy 13 at 11 to 13 D6 weeks of gestation

Sonographic screening for trisomy 13 at 11 to 13 D6 weeks of gestation American Journal of Obstetrics and Gynecology (2006) 194, 397 401 www.ajog.org Sonographic screening for trisomy 13 at 11 to 13 D6 weeks of gestation Aris T. Papageorghiou, MD, a Kyriaki Avgidou, MD, a

More information

X X X a) perfect linear correlation b) no correlation c) positive correlation (r = 1) (r = 0) (0 < r < 1)

X X X a) perfect linear correlation b) no correlation c) positive correlation (r = 1) (r = 0) (0 < r < 1) CORRELATION AND REGRESSION / 47 CHAPTER EIGHT CORRELATION AND REGRESSION Correlation and regression are statistical methods that are commonly used in the medical literature to compare two or more variables.

More information

INTERGROWTH-21 st International Fetal and Newborn Growth Standards for the 21 st Century

INTERGROWTH-21 st International Fetal and Newborn Growth Standards for the 21 st Century INTERGROWTH-21 st CRL standardization 1 INTERGROWTH-21 st International Fetal and Newborn Growth Standards for the 21 st Century The International Fetal and Newborn Growth Consortium Correct measurement

More information

Differentiation between normal and abnormal fetal growth

Differentiation between normal and abnormal fetal growth Differentiation between normal and abnormal fetal growth JASON GARDOSI MD FRCSE FRCOG Director, West Midlands Perinatal Institute, St Chad s Court, 213 Hagley Road, Birmingham B16 9RG, U.K. Tel +44 (0)121

More information

FIRST-TRIMESTER DOWN S SYNDROME SCREENING

FIRST-TRIMESTER DOWN S SYNDROME SCREENING FIRST-TRIMESTER DOWN S SYNDROME SCREENING BY FETAL NUCHAL TRANSLUCENCY MEASUREMENT IN TAIWAN Hei-Jen Jou, 1,2 Jin-Chung Shih, 2 Shiao-Chi Wu, 3 Te-Cheng Li, 1 Chau-Yang Tzeng, 1 and Fon-Jou Hsieh 2 Background:

More information

The high mortality rates of ovarian cancer are

The high mortality rates of ovarian cancer are Volumes of Normal Ovaries, Ovaries with Benign Lesions, and Ovaries with Cancer in Menopausal Women: Is There an Optimal Cut-off Value to Predict Malignancy? Rami Aviram, MD, 1,3 Gilad Gassner, MD, 2 Ofer

More information

Surface area measurement using rendered three-dimensional ultrasound imaging: an in-vitro phantom study

Surface area measurement using rendered three-dimensional ultrasound imaging: an in-vitro phantom study Ultrasound Obstet Gynecol 211; 38: 445 449 Published online 13 September 211 in Wiley Online Library (wileyonlinelibrary.com). DOI: 1.12/uog.8984 Surface area measurement using rendered three-dimensional

More information

Diagnostic Medical Sonography

Diagnostic Medical Sonography H. Councill Trenholm State Technical College 151 Location: Trenholm Campus Program Information Sonography, or ultrasonography, is the use of sound waves to generate an image for the assessment and diagnosis

More information

This document covers the principles behind Gestation Adjusted Optimal Weight (GROW) for the following applications

This document covers the principles behind Gestation Adjusted Optimal Weight (GROW) for the following applications This document covers the principles behind Gestation Adjusted Optimal Weight (GROW) for the following applications GROW-CC (customised centiles) - for calculating weight centiles individually or in a spreadsheet;

More information

Guideline for the management of reduced fetal movements after 24 weeks gestation.

Guideline for the management of reduced fetal movements after 24 weeks gestation. Title of Guideline (must include the word Guideline (not protocol, policy, procedure etc) Author: Contact Name and Job Title Directorate & Speciality Date of submission Explicit definition of patient group

More information

Statistical considerations for the development of prescriptive fetal and newborn growth standards in the INTERGROWTH-21 st Project

Statistical considerations for the development of prescriptive fetal and newborn growth standards in the INTERGROWTH-21 st Project DOI: 10.1111/1471-0528.12031 www.bjog.org Original article Statistical considerations for the development of prescriptive fetal and newborn growth standards in the INTERGROWTH-21 st Project DG Altman,

More information

Chapter 10. Key Ideas Correlation, Correlation Coefficient (r),

Chapter 10. Key Ideas Correlation, Correlation Coefficient (r), Chapter 0 Key Ideas Correlation, Correlation Coefficient (r), Section 0-: Overview We have already explored the basics of describing single variable data sets. However, when two quantitative variables

More information

High-resolution sonography has enabled us to

High-resolution sonography has enabled us to Original Article 12 Preliminary Normal Reference Values of Nuchal Translucency Thickness in Taiwanese Fetuses at 11-14 Weeks of Gestation Jenn-Jeih Hsu, MD; Ching-Chang Hsieh, MD; Chi-Hsin Chiang, MD;

More information

Antenatal Guidelines. No.43 Women who present with early pregnancy pain +/- bleeding, or early pregnancy loss within EPU dept.

Antenatal Guidelines. No.43 Women who present with early pregnancy pain +/- bleeding, or early pregnancy loss within EPU dept. Antenatal Guidelines No.43 Women who present with early pregnancy pain +/- bleeding, or early pregnancy loss within EPU dept. 1. Introduction Women with early pregnancy problems have access to a dedicated

More information

Accuracy of Ultrasound Estimation of Fetal Weight by Obstetrics and Gynaecology Residents and Maternal-fetal Medicine Subspecialists

Accuracy of Ultrasound Estimation of Fetal Weight by Obstetrics and Gynaecology Residents and Maternal-fetal Medicine Subspecialists Ultrasound Estimation of Fetal Weight Accuracy of Ultrasound Estimation of Fetal Weight by Obstetrics and Gynaecology Residents and Maternal-fetal Medicine Subspecialists PKS YAU MBChB, MRCOG (UK) WK SIN

More information

Maternity Care Primary C-Section Rate Specifications 2014 (07/01/2013 to 06/30/2014 Dates of Service)

Maternity Care Primary C-Section Rate Specifications 2014 (07/01/2013 to 06/30/2014 Dates of Service) Summary of Changes Denominator Changes: Two additions were made to the denominator criteria. The denominator was changed to include patients who had: a vertex position delivery AND a term pregnancy of

More information

Descriptive Statistics

Descriptive Statistics Descriptive Statistics Primer Descriptive statistics Central tendency Variation Relative position Relationships Calculating descriptive statistics Descriptive Statistics Purpose to describe or summarize

More information

The role of ultrasound in determining fetal sex

The role of ultrasound in determining fetal sex Original article The role of ultrasound in determining fetal sex Sifrash Meseret Gelaw 1, Hirut Bisrat 2 Abstract Background: The gender of a fetus is necessary to know for many different reasons. There

More information

Outline of Topics. Statistical Methods I. Types of Data. Descriptive Statistics

Outline of Topics. Statistical Methods I. Types of Data. Descriptive Statistics Statistical Methods I Tamekia L. Jones, Ph.D. (tjones@cog.ufl.edu) Research Assistant Professor Children s Oncology Group Statistics & Data Center Department of Biostatistics Colleges of Medicine and Public

More information

Ultrasound Examinations Performed by Nurses in Obstetric, Gynecologic, and Reproductive Medicine Settings: Clinical Competencies and Education Guide

Ultrasound Examinations Performed by Nurses in Obstetric, Gynecologic, and Reproductive Medicine Settings: Clinical Competencies and Education Guide Ultrasound Examinations Performed by Nurses in Obstetric, Gynecologic, and Reproductive Medicine Settings: Clinical Competencies and Education Guide 3rd Edition The Association of Women s Health, Obstetric

More information

CONFIDENT CODING FOR OB/GYN CONFIDENT CODING FOR OB/GYN

CONFIDENT CODING FOR OB/GYN CONFIDENT CODING FOR OB/GYN Arlene J. Smith, CPC AAPC National Advisory Board 2007-2009 1 So when exactly does the global period start? Unraveling the confusion in antepartum care coding Correct coding for multiple gestations! Vaginal

More information

School of Diagnostic Medical Sonography Course Catalog

School of Diagnostic Medical Sonography Course Catalog School of Diagnostic Medical Sonography Course Catalog 2 School of Diagnostic Medical Sonography Course Schedule Our program provides a broad base of education and performance- based clinical experience

More information

INTRODUCTION. Folorunsho B. Adewale 1, Munir deen A. Ijaiya 2 ORIGINAL ARTICLE. NJOG 2011 Nov-Dec; 6 (2): 27-32

INTRODUCTION. Folorunsho B. Adewale 1, Munir deen A. Ijaiya 2 ORIGINAL ARTICLE. NJOG 2011 Nov-Dec; 6 (2): 27-32 NJOG 2011 Nov-Dec; 6 (2): 27-32 ORIGINAL ARTICLE Symphysio-Fundal Height Measurement as a Means of Gestational Age Assessment in the Second Half of Pregnancy at the University of Ilorin Teaching Hospital,

More information

Def: The standard normal distribution is a normal probability distribution that has a mean of 0 and a standard deviation of 1.

Def: The standard normal distribution is a normal probability distribution that has a mean of 0 and a standard deviation of 1. Lecture 6: Chapter 6: Normal Probability Distributions A normal distribution is a continuous probability distribution for a random variable x. The graph of a normal distribution is called the normal curve.

More information

Multiple Pregnancies: Determining Chorionicity and Amnionicity

Multiple Pregnancies: Determining Chorionicity and Amnionicity Thomas Jefferson University Jefferson Digital Commons Department of Radiologic Sciences Faculty Papers Department of Radiologic Sciences January 2006 Multiple Pregnancies: Determining Chorionicity and

More information

First Trimester Pregnancy Complications

First Trimester Pregnancy Complications First Trimester Pregnancy Complications Diagnosis and Management Mark Deutchman MD University of Colorado Objectives Correlation of clincal, ultrasound and serum hcg findings to make a diagnosis Make sense

More information

3D Ultrasound. Outline. What is 3D US? Volume Sonography. 3D Ultrasound in Obstetrics: Current Modalities & Future Potential. Alfred Abuhamad, M.D.

3D Ultrasound. Outline. What is 3D US? Volume Sonography. 3D Ultrasound in Obstetrics: Current Modalities & Future Potential. Alfred Abuhamad, M.D. in Obstetrics: Current Modalities & Future Potential Outline What is 3D US? What are obvious advantages of 3D US? What is the future of 3D US? Alfred Abuhamad, M.D. Eastern Virginia Medical School 2D US

More information

ABSTRACT Background Screening for trisomy 21 (Down s syndrome) by measuring maternal serum alphafetoprotein,

ABSTRACT Background Screening for trisomy 21 (Down s syndrome) by measuring maternal serum alphafetoprotein, INCREASED NUCHAL TRANSLUCENCY AS A MARKER FOR FETAL CHROMOSOMAL DEFECTS PEKKA TAIPALE, M.D., VILHO HIILESMAA, M.D., PH.D., RIITTA SALONEN, M.D., PH.D., AND PEKKA YLÖSTALO, M.D., PH.D. ABSTRACT Background

More information

Simplified protocol of nuchal translucency measurement: Is it still effective?

Simplified protocol of nuchal translucency measurement: Is it still effective? Original Article Obstet Gynecol Sci 2013;56(5):307-311 http://dx.doi.org/10.5468/ogs.2013.56.5.307 pissn 2287-8572 eissn 2287-8580 Simplified protocol of nuchal translucency measurement: Is it still effective?

More information

Evaluation of endometrial receptivity during in-vitro fertilization using three-dimensional power Doppler ultrasound

Evaluation of endometrial receptivity during in-vitro fertilization using three-dimensional power Doppler ultrasound Ultrasound Obstet Gynecol 2005; 26: 765 769 Published online 4 November 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.2628 Evaluation of endometrial receptivity during in-vitro

More information

A reassessment of biochemical marker distributions in trisomy 21-affected and unaffected twin pregnancies in the first trimester

A reassessment of biochemical marker distributions in trisomy 21-affected and unaffected twin pregnancies in the first trimester Ultrasound Obstet Gynecol 2011; 37: 38 47 Published online 7 December 2010 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/uog.8845 A reassessment of biochemical marker distributions in

More information

Fetal Lateral Ventricular Width: What Should Be Its Upper Limit?

Fetal Lateral Ventricular Width: What Should Be Its Upper Limit? Article Fetal Lateral Ventricular Width: What Should Be Its Upper Limit? A Prospective Cohort Study and Reanalysis of the Current and Previous Data Benny Almog, MD, Ronni Gamzu, MD, PhD, Reuven Achiron,

More information

Decision Support for Fetal Gestation Age Estimation

Decision Support for Fetal Gestation Age Estimation Decision Support for Fetal Gestation Age Estimation Abstract Peter Summons *, Warwick Giles**, Greg Gibbon * *Information Systems Group School of Management The University of Newcastle, Australia **Discipline

More information

CALCULATIONS & STATISTICS

CALCULATIONS & STATISTICS CALCULATIONS & STATISTICS CALCULATION OF SCORES Conversion of 1-5 scale to 0-100 scores When you look at your report, you will notice that the scores are reported on a 0-100 scale, even though respondents

More information

SONOGRAPHIC EVALUATION OF PLACENTAL THICKNESS AN INDICATOR OF GESTATIONAL AGE Anu Kapoor 1, Mahesh D. Dudhat 2

SONOGRAPHIC EVALUATION OF PLACENTAL THICKNESS AN INDICATOR OF GESTATIONAL AGE Anu Kapoor 1, Mahesh D. Dudhat 2 SONOGRAPHIC EVALUATION OF PLACENTAL THICKNESS AN INDICATOR OF GESTATIONAL AGE Anu Kapoor 1, Mahesh D. Dudhat 2 1 Associate Professor, Department of Radiology, Nizam s Institute of Medical Sciences, Hyderabad,

More information

Prediction of Pregnancy Outcome Using HCG, CA125 and Progesterone in Cases of Habitual Abortions

Prediction of Pregnancy Outcome Using HCG, CA125 and Progesterone in Cases of Habitual Abortions Prediction of Pregnancy Outcome Using HCG, CA125 and Progesterone in * (MBChB, FICMS, CABOG) **Sawsan Talib Salman (MBChB, FICMS, CABOG) ***Huda Khaleel Ibrahim (MBChB) Abstract Background: - Although

More information

School of Diagnostic Medical Sonography Course Catalog

School of Diagnostic Medical Sonography Course Catalog School of Diagnostic Medical Sonography Course Catalog 2 School of Diagnostic Medical Sonography Course Schedule Our program provides a broad base of education and performance- based clinical experience

More information

Fetal loss following ultrasound diagnosis of a live fetus at 6 10 weeks of gestation

Fetal loss following ultrasound diagnosis of a live fetus at 6 10 weeks of gestation Ultrasound Obstet Gynecol 23; 22: 368 372 Published online 2 September 23 in Wiley InterScience (www.interscience.wiley.com). DOI: 1.12/uog.24 Fetal loss following ultrasound diagnosis of a live fetus

More information

GYNAECOLOGY. Ahmed Mohamed Abbas*, Mohamed Khalaf*, Abd El-Aziz E. Tammam**, Ahmed H. Abdellah**, Ahmed Mwafy**. Introduction ABSTRACT

GYNAECOLOGY. Ahmed Mohamed Abbas*, Mohamed Khalaf*, Abd El-Aziz E. Tammam**, Ahmed H. Abdellah**, Ahmed Mwafy**. Introduction ABSTRACT Thai Journal of Obstetrics and Gynaecology April 2015, Vol. 23, pp. 113-117 GYNAECOLOGY The Diagnostic Value of Saline Infusion Sonohysterography Versus Hysteroscopy in Evaluation of Uterine Cavity in

More information

Maternal Smoking and Fetal Growth Characteristics in Different Periods of Pregnancy

Maternal Smoking and Fetal Growth Characteristics in Different Periods of Pregnancy American Journal of Epidemiology Copyright ª 2007 by the Johns Hopkins Bloomberg School of Public Health All rights reserved; printed in U.S.A. Vol. 165, No. 10 DOI: 10.1093/aje/kwm014 Advance Access publication

More information

MINIMUM CORD LENGTH TO ALLOW SPONTANEOUS VAGINAL DELIVERY. Gene E. LaMonica, MD. Margaret L. Wilson, BA. Anne M. Fullilove, BS. William F.

MINIMUM CORD LENGTH TO ALLOW SPONTANEOUS VAGINAL DELIVERY. Gene E. LaMonica, MD. Margaret L. Wilson, BA. Anne M. Fullilove, BS. William F. Brief Communication MINIMUM CORD LENGTH TO ALLOW SPONTANEOUS VAGINAL DELIVERY Gene E. LaMonica, MD Margaret L. Wilson, BA Anne M. Fullilove, BS William F. Rayburn, MD Running title: Short umbilical cord

More information

The value of ultrasound in the prediction of successful induction of labor

The value of ultrasound in the prediction of successful induction of labor Ultrasound Obstet Gynecol 2004; 24: 538 549 Published online 27 August 2004 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.1100 The value of ultrasound in the prediction of successful

More information

Lean Six Sigma Analyze Phase Introduction. TECH 50800 QUALITY and PRODUCTIVITY in INDUSTRY and TECHNOLOGY

Lean Six Sigma Analyze Phase Introduction. TECH 50800 QUALITY and PRODUCTIVITY in INDUSTRY and TECHNOLOGY TECH 50800 QUALITY and PRODUCTIVITY in INDUSTRY and TECHNOLOGY Before we begin: Turn on the sound on your computer. There is audio to accompany this presentation. Audio will accompany most of the online

More information

Irregular Yolk Sac Shape

Irregular Yolk Sac Shape ORIGINAL RESEARCH Irregular Yolk Sac Shape Is It Really Associated With an Increased Risk of Spontaneous Abortion? Sinan Tan, MD, Ali I pek, MD, Mine Kanat Pektas, MD, Meral Arifoğlu, MD, Mehmet Akif Teber,

More information

Sonographic Appearance of Early Complete Molar Pregnancies

Sonographic Appearance of Early Complete Molar Pregnancies Sonographic Appearance of Early Complete Molar Pregnancies Elizabeth Lazarus, MD, Carol A. Hulka, MD, Bettina Siewert, MD, Deborah Levine, MD Since our anecdotal experience indicates that the classically

More information

Stats Review Chapters 3-4

Stats Review Chapters 3-4 Stats Review Chapters 3-4 Created by Teri Johnson Math Coordinator, Mary Stangler Center for Academic Success Examples are taken from Statistics 4 E by Michael Sullivan, III And the corresponding Test

More information

Table 1: CPT codes for multiple ultrasounds

Table 1: CPT codes for multiple ultrasounds Coding for multiple ultrasounds By Emily H. Hill, PA In the June 2004 issue [pp 90-97], I discussed the coding guidelines for reporting multiple surgical procedures. There are also instances in which multiple

More information

Screening for chromosomal abnormalities at 10 14 weeks: the role of ductus venosus blood flow

Screening for chromosomal abnormalities at 10 14 weeks: the role of ductus venosus blood flow Ultrasound Obstet Gynecol 1998;12:380 384 Screening for chromosomal abnormalities at 10 14 weeks: the role of ductus venosus blood flow A. Matias*, C. Gomes*, N. Flack*, N. Montenegro and K. H. Nicolaides*

More information

IN THIS ISSUE. Sponsored by Perinatal Quality Foundation

IN THIS ISSUE. Sponsored by Perinatal Quality Foundation Sponsored by Perinatal Quality Foundation The ExaminerFall 2014 The overall frequency of the common aneuploidies (Trisomy 21, 18, 13) screened for by NIPT is approximately two per thousand pregnancies

More information

1) The table lists the smoking habits of a group of college students. Answer: 0.218

1) The table lists the smoking habits of a group of college students. Answer: 0.218 FINAL EXAM REVIEW Name ) The table lists the smoking habits of a group of college students. Sex Non-smoker Regular Smoker Heavy Smoker Total Man 5 52 5 92 Woman 8 2 2 220 Total 22 2 If a student is chosen

More information

Answer: C. The strength of a correlation does not change if units change by a linear transformation such as: Fahrenheit = 32 + (5/9) * Centigrade

Answer: C. The strength of a correlation does not change if units change by a linear transformation such as: Fahrenheit = 32 + (5/9) * Centigrade Statistics Quiz Correlation and Regression -- ANSWERS 1. Temperature and air pollution are known to be correlated. We collect data from two laboratories, in Boston and Montreal. Boston makes their measurements

More information

Screening for trisomy 21 by fetal tricuspid regurgitation, nuchal translucency and maternal serum free β-hcg and PAPP-A at 11 + 0to13+ 6 weeks

Screening for trisomy 21 by fetal tricuspid regurgitation, nuchal translucency and maternal serum free β-hcg and PAPP-A at 11 + 0to13+ 6 weeks Ultrasound Obstet Gynecol 2006; 27: 151 155 Published online 30 December 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.2699 Screening for trisomy 21 by fetal tricuspid regurgitation,

More information

Effect of Increased Body Mass Index on the Accuracy of Estimated Fetal Weight by Sonography in Twins

Effect of Increased Body Mass Index on the Accuracy of Estimated Fetal Weight by Sonography in Twins Article Effect of Increased Body Mass Index on the Accuracy of Estimated Fetal Weight by Sonography in Twins Manisha Gandhi, MD, Lauren Ferrara, MD, Victoria Belogolovkin, MD, Erin Moshier, MS, Andrei

More information

WHAT IS A JOURNAL CLUB?

WHAT IS A JOURNAL CLUB? WHAT IS A JOURNAL CLUB? With its September 2002 issue, the American Journal of Critical Care debuts a new feature, the AJCC Journal Club. Each issue of the journal will now feature an AJCC Journal Club

More information

Simple linear regression

Simple linear regression Simple linear regression Introduction Simple linear regression is a statistical method for obtaining a formula to predict values of one variable from another where there is a causal relationship between

More information

Pelvic Ultrasonography in Turner Syndrome: Standards for Uterine and Ovarian Volume

Pelvic Ultrasonography in Turner Syndrome: Standards for Uterine and Ovarian Volume Pelvic Ultrasonography in Turner Syndrome: Standards for Uterine and Ovarian Volume Hans P. Haber, MD, Michael B. Ranke, MD The purpose of this study was to investigate uterine and ovarian size according

More information

BELIEVE MIDWIFERY SERVICES, LLC

BELIEVE MIDWIFERY SERVICES, LLC , LLC TITLE: ESTABLISHING the GESTATIONAL AGE & ROUTINE ULTRASOUND EFFECTIVE DATE: November 11th, 2013 POLICY STATEMENT Establishing accurate pregnancy dating impacts the management of normal and abnormal

More information

Non-Invasive Prenatal Testing Information for medical practitioners

Non-Invasive Prenatal Testing Information for medical practitioners Non-Invasive Prenatal Testing Information for medical practitioners Harmony Prenatal Test evaluates the risk for trisomies 21, 18 and 13 in women of any age or risk category Since non-invasive prenatal

More information

Editorial. From nuchal translucency to intracranial translucency: towards the early detection of spina bifida. R. CHAOUI *and K. H.

Editorial. From nuchal translucency to intracranial translucency: towards the early detection of spina bifida. R. CHAOUI *and K. H. Ultrasound Obstet Gynecol 2010; 35: 133 138 Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.7552 Editorial From nuchal translucency to intracranial translucency: towards

More information

Simple Predictive Analytics Curtis Seare

Simple Predictive Analytics Curtis Seare Using Excel to Solve Business Problems: Simple Predictive Analytics Curtis Seare Copyright: Vault Analytics July 2010 Contents Section I: Background Information Why use Predictive Analytics? How to use

More information

Ultrasonographic Determination of Equine Fetal Gender (31 Mar 2000)

Ultrasonographic Determination of Equine Fetal Gender (31 Mar 2000) In: Recent Advances in Equine Theriogenology, B.A. Ball (Ed.) Publisher: International Veterinary Information Service (www.ivis.org) Ultrasonographic Determination of Equine Fetal Gender (31 Mar 2000)

More information

Counselling Session for IVF/ET patients

Counselling Session for IVF/ET patients Page Page 1 of 9 Counselling Session for IVF/ET patients 1. Please attend the following counselling session. Place: Seminar Room, Room 509, 5/F, Block K, Queen Mary Hospital Lecture Theatre, Room 602,

More information

School of Diagnostic Medical Sonography

School of Diagnostic Medical Sonography Semester 1 Orientation - 101 This class is an introduction to sonography which includes a basic anatomy review, introduction to sonographic scanning techniques and physical principles. This curriculum

More information

Reference values for umbilical cord diameters in placenta specimens

Reference values for umbilical cord diameters in placenta specimens 1 2 3 Reference values for umbilical cord diameters in placenta specimens H. Pinar 1, Murat Iyigün 2 4 5 6 7 8 9 10 Halit Pinar, MD Brown Medical School Women and Infants Hospital Division of Perinatal

More information

Ultrasound of Fetal Biometrics and Growth

Ultrasound of Fetal Biometrics and Growth 1 of 10 5/3/2005 8:30 PM Ultrasound of Fetal Biometrics and Growth Contents: Section 1: Ultrasound Measure of Fetal Size: Biometrics Section 2: Individual Measurement Characteristics and Techniques Section

More information

Tools of Algebra. Solving Equations. Solving Inequalities. Dimensional Analysis and Probability. Scope and Sequence. Algebra I

Tools of Algebra. Solving Equations. Solving Inequalities. Dimensional Analysis and Probability. Scope and Sequence. Algebra I Scope and Sequence Algebra I Tools of Algebra CLE 3102.1.1, CFU 3102.1.10, CFU 3102.1.9, CFU 3102.2.1, CFU 3102.2.2, CFU 3102.2.7, CFU 3102.2.8, SPI 3102.1.3, SPI 3102.2.3, SPI 3102.4.1, 1-2 Using Variables,

More information

BE-SAFE: Bedside Sonography for Assessment of the Fetus in. Fetus in Emergencies: Educational Intervention for Latepregnancy. Obstetric Ultrasound

BE-SAFE: Bedside Sonography for Assessment of the Fetus in. Fetus in Emergencies: Educational Intervention for Latepregnancy. Obstetric Ultrasound BE-SAFE: Bedside Sonography for Assessment of the Fetus in Emergencies: Educational Intervention for Late-pregnancy Obstetric Ultrasound The Harvard community has made this article openly available. Please

More information

e = random error, assumed to be normally distributed with mean 0 and standard deviation σ

e = random error, assumed to be normally distributed with mean 0 and standard deviation σ 1 Linear Regression 1.1 Simple Linear Regression Model The linear regression model is applied if we want to model a numeric response variable and its dependency on at least one numeric factor variable.

More information

A single center experience with 1000 consecutive cases of multifetal pregnancy reduction

A single center experience with 1000 consecutive cases of multifetal pregnancy reduction A single center experience with 1000 consecutive cases of multifetal pregnancy reduction Joanne Stone, MD, Keith Eddleman, MD, Lauren Lynch, MD, and Richard L. Berkowitz, MD New York, NY, and San Juan,

More information