Periods, Scans, and Due Dates: What To Do With What You ve Got

Transcription

1 Periods, Scans, and Due Dates: What To Do With What You ve Got Marc Jackson MD Maternal Fetal Medicine Intermountain Healthcare University of Utah School of Medicine

2 Why An Accurate EDC is Important Timing of care Interpretation of exam findings Interpretation of test results Management of early (?) labor or prolonged (?) pregnancy Patients just want to know

3 Using the LMP Why do we use it? We (the patient) can see it Historical basis

4 Using the LMP But the LMP assumes certain things: Accurate recollection Regular menses 28-day cycles Ovulation on day 14 (Oh, come on. Really?) Yes, but it is good enough most of the time

5 The Rise of the Machines

6 Ultrasound at the First OB Visit Commonly practiced Almost always enjoyed by patients Often useful Sometimes causes more trouble than not Diagnostic US vs Sightseeing US

7 Early Ultrasound Timeline Gestational sac: ~ 4.5 weeks Yolk sac: ~ weeks Embryo with cardiac motion: Transvaginal: ~ weeks Transabdominal: it depends

8 Early Ultrasound Milestones Some guidelines: Embryo should be seen if mean sac diameter is > ~ 20 mm Cardiac activity should be seen if embryo CRL > 5 7 mm When in doubt: Refer to MFM or Radiology Repeat exam in about a week

9 Speaking of Cardiac Activity Patients want to hear the heartbeat Pulse Wave Doppler uses higher energy than 2D or M-mode Higher energy increases chance of a biologic effect No diagnostic/medical benefit to using PW to audiblize the FHR Don t use it. Tell patient why.

10 Early Ultrasound for GA Gestational sac diameters Three perpendicular planes Don t use GS for GA assignment! Crown-rump length of embryo 6 to 13 6/7 weeks Average of 3 values Right way and wrong ways to do it BPD/HC/AC/FL 14 0/7 weeks and beyond

11 Gestational Sac Diameters

12 A Good CRL

13 Please Don t Measure This Nope. Negatory. Unh uh. Not helpful.

14 A Good CRL Avoid the pitfall of including the Yolk Sac in the CRL in early gestation.

15 See the FHR, Don t Hear It

16 Early OB Office US Conclusions Please don t assign GA with a Sightseeing Ultrasound exam It s OK to tell the patient what it is Don t use gest sac measurements for assigning gestational age Don t use CRL after 13 6/7 weeks Don t use PW Doppler

17 Early Ultrasound for Dating ACOG CO 611: US measurement up to and including 13 6/7 weeks is the most accurate method to establish or confirm gestational age. This DOES NOT imply that all patients need a first-trimester ultrasound. A reliable LMP and week confirmatory ultrasound is sufficient for gestational dating.

18 Ultrasound for Dating ACOG PB 175: At various gestational ages, ultrasound examination is an accurate method of determining gestational age and it is recommended for all pregnant patients. ACOG PB 175, 2016

19 Ultrasound for Dating ACOG PB 175: In the absence of other specific indications, the optimal time for a single ultrasound examination is at weeks of gestation. This timing allows for a survey of fetal anatomy in most women and an accurate estimation of gestational age. ACOG PB 175, 2016

20 When Should We Change EDC? ACOG CO 611, 2014

21 This is all great, but we ve got a few patients who don t present for care in the first trimester. Or the second. What do we do about them?

22 Suboptimal Gestational Dating Pregnancies without an ultrasound confirming or revising the estimated due date prior to 22 0/7 weeks gestational age should be considered suboptimally dated. What do we do and when do we do it with this (very real) patient?

23 The Suboptimally Dated Patient Get an ultrasound anyway Put the whole story together and assign an honest best obstetric estimate Acknowledge the uncertainty and discuss with the patient Don t change GA once it s set

24 The Suboptimally Dated Patient Use the best obstetric estimate for routine management (glucola, GBS, etc.) Consider another US 3-4 weeks later Intended to support your GA choice Can identify suboptimal growth IUGR Again: Don t change GA once it s set Again: Remember the imprecision and uncertainty in making management decisions

25 The Suboptimally Dated Patient: Late Term Gestation Management GA may be weeks later than you think GA assigned by US at 28 weeks may actually be 25+ to 30+ Consider FHR testing and AFV measurement at weeks Delivery is indicated at 41 weeks

26 The Suboptimally Dated Patient: Delivery Management Use best obstetric estimate regarding management of spontaneous labor For patients with prior cesarean: TOLAC awaits spontaneous labor Repeat CS scheduled at 39 weeks Discuss risk of neonatal morbidity related to uncertain GA No amniocentesis

27 The Suboptimally Dated Patient: Role of Amniocentesis for FLM Poor reliability in predicting neonatal outcomes Late preterm and early term babies with mature FLM are at increased risk for respiratory morbidity compared to babies at > 39 wks Non-respiratory morbidities Amnio for FLM not recommended

28 The Suboptimally Dated Patient: Delivery Management Medically-indicated delivery timing: Use best obstetric estimate There is no better alternative Elective delivery:. No role for elective delivery in the suboptimally dated pregnancy. Nope. Sorry, ma am. Can t do it.

29 The Suboptimally Dated Patient: Corticosteroids There are no data on which to guide a recommendation. Use best obstetric estimate when managing patients at risk for early delivery Use standard guidelines Be liberal with corticosteroid use in the week window

30 The Suboptimally Dated Patient: Conclusions Pregnancies without an ultrasound before 22 weeks that confirms/assigns a gestational age are considered suboptimally dated. Get an ultrasound anyway, recognizing its imprecision Use the best obstetric estimate for decision-making Consider follow-up ultrasound in 3 4 weeks to confirm normal growth

31 The Suboptimally Dated Patient: Conclusions Err on the side of caution with regard to prematurity Low threshold for giving steroids before about 36 weeks Err on the side of caution with regard to postmaturity Initiate testing at weeks Deliver by 41 weeks

32 The Suboptimally Dated Patient: Conclusions Medically-indicated and obstetricallyindicated inductions are timed using best estimate. Scheduled repeat CS are done at 39 weeks. No elective inductions. No amniocentesis for FLM. Communicate uncertainty and risk to patient in advance.

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