Pregnancy and Thyroid Disease - Facts and Figures

Transcription

1 Pregnancy and Thyroid Disease - Pregestation women] Gestation Facts and Figures Overt hypothyroidism 3-12/1000 [Child bearing age Thyr Antibodies [TPOAb] 10% Hypothyroidism (TSH) 2-3.0% [Overt %, subclinical 2-5%] Hypothyroxinaemia 2% Hyperthyroidism 0.2% Thyroid Nodules 3-21% Vanderpump 2011 Postpartum PPTD 5-9% PP depression 30% [ vs 20%] PP Graves up to 40% of Graves

2 GUIDELINE TOPICS ATA TFTs Hypothyroidism Hyperthyroidism Spontaneous pregnancy loss,preterm delivery,thyroid antibodies Thyroid nodules and cancer PPT Screening 84 Questions. 76 Recommendations ENDO Hypo Hyper Hyperemesis and hyperthyroidism AITD and miscarriage Thyroid nodules and cancer Iodine nutrition PPT Screening

3 Iodine Status and Pregnancy Pregnant and lactating requirement 250µg/day [de Benoist & Delange 2007 Pub Hlth Nutr] Iodine deficiency results in neurodevelopmental delay [Vermiglio et al 1999, de Escobar et al 2007] Iodine supplementation improves child neurocognitive outcome [Velasco et al 2009 JCEM, Berbel et al 2009 Thyroid] Sustained I intake of 500µg µg/day should be avoided because of concerns about fetal hyperthyroidism

4 Antithyroid drug treatment PTU is preferred for the treatment of hyperthyroidism in the first trimester. Patients on MMI should be switched to PTU if pregnancy is confirmed in the first trimester. Following the first trimester, consideration should be given to switching to MMI (hepatotoxicity of PTU) Level I- USPSTF[ATA] Propylthiouracil, if available, has been recommended as the first-line drug for treatment of hyperthyroidism during the first trimester of pregnancy, because of the possible association of methimazole with congenital abnormalities that occur during 1st trimester organogenesis [ENDO] Available data indicate that MMI and PTU are equally efficacious in treatment of pregnant women. Practitioners should use their clinical judgment in choosing the therapy [ENDO]

5 Hyperthyroidism and lactation MMI in doses up to mg/d is safe for lactating mothers and their infants. PTU at doses up to 300 mg/d is a second-line agent due to concerns about severe hepatotoxicity. ATDs should be administered following a feeding and in divided doses. Level A-USPSTF[ATA] Four recent studies reported no alteration in thyroid function in a total of 159 newborns breastfed by mothers treated with daily doses of PTU ( mg), MMI (5-20 mg), or carbimazole (5-15 mg) for periods ranging from 3 weeks to 8 months [ENDO] ATD therapy (PTU <300 mg/day, MMI <20 mg/day) may be considered during lactation, [ENDO]

6 TPO Antibodies and Pregnancy Presence of TPOAb is a risk factor for: 1.Miscarriage [Thangaratinam et al BMJ 2011] 2.Progression of hypothyroidism [ Glinoer et al JCEM 1994] 3.Preterm delivery [Stagnaro-Green et al Thyroid 2005] 4.Post partum thyroiditis [Premawardhana et al 2004] Treat with L-T4 if TSH> 2.5mU/L

7 Recommendations ATA Insufficient evidence for: Screening for thyroid antibodies L-T4 therapy in TPOAb +ve women in pregnancy L-T4 in women having ART Screening and L-T4 to prevent preterm delivery ENDO However, since women with elevated anti-tpo antibodies are at increased risk for progression of hypothyroidism, if identified such women should be screened for serum TSH abnormalities before pregnancy, as well as during the 1st and 2nd trimesters of pregnancy. (USPSTF Recommendation level: C, Evidence-fair) (GRADE 2 )

8 Management of Hypothyroidism [ENDO] Caution in the interpretation of serum free T4 levels during pregnancy Overt maternal hypothyroidism is known to have serious adverse effects on the fetus.. SCH: potential benefits outweigh the potential risks, the panel recommends thyroxine replacement, Adjustment of the preconception thyroxine dose to reach prior to pregnancy a TSH level not higher than 2.5 miu/l T4 dose usually needs to be incremented by 4 to 6 weeks gestation, and may require a 30% or more increase Overt hypothyroidism during pregnancy: TFTs normalized as rapidly as possible. L-T4 dosage titrated rapidly serum TSH <2.5 miu/l 1 st trimester ( 3 miu/l in 2 nd & 3rd) to trimester-specific TSH ranges. TFTs re-measured within days AITD & euthyroid in early pregnancy: monitored for elevation of TSH. After delivery, most hypothyroid women need to decrease the thyroxine dosage.

9 Isolated Hypothyroxinaemia ATA: Should not be treated ENDO: No specific recommendation

10 THYROID NODULES ATA Guidelines 2011

11 POST PARTUM THYROID DISEASE PPT is common Significant cause of PP maternal morbidity May result in permanent hypothyroidism Easily treated Probably could be screened for Women known to be TPOAb+ve should have TSH at 3 & 6 months postpartum In type 1 DM TSH at 3 and 6 months post partum Annual TSH in women with a history of PPT a) PPT with TSH < 10 not planning further pregnancy probably no intervention b) PPT with TSH > 10 planning further pregnancy TREAT Evidence for association between PPT and depression inconclusive

12 Justification for Screening Test Well defined disorder with known incidence/prevalence Medically important disorder Screening test simple and safe with established cut off values Effective treatment available Cost of test relative to benefit should be known Adequate logistics for the testing and follow up Patient and management acceptability YES YES YES YES YES YES YES Maternal Thyroid Disease Frequency of hypothyroidism Effects on mother and child Effectiveness of screening strategies Effectiveness of intervention Wald N, Law M Medical Screening in Oxford Textbook of Medicine th Ed pp94 108

13 Question 83: Should all pregnant women be screened for serum TSH level in the first trimester of pregnancy? ATA There is insufficient evidence to recommend for or against universal TSH screening at the first trimester visit. Level I Because no studies to date have demonstrated a benefit to treatment of isolated maternal hypothyroximenia, universal FT4 screening of pregnant women is not recommended. Level D There is insufficient evidence to recommend for or against TSH testing preconception in women at high risk for hypothyroidism. Level I

14 Current Views on Screening ATA: Not enough evidence for or against universal TSH screening ENDO: No agreement with regard to screening recommendations for all newly pregnant women. Some members recommended screening of all pregnant women for serum TSH abnormalities by the 9th week or at the time of their first visit. (USPSTF Recommendation level: C, Evidence level-fair; (GRADE 2 ) Some members recommended neither for nor against universal screening of all pregnant women for TSH abnormalities at the time of their first visit. All strongly support aggressive case finding to identify and test high-risk women for elevated TSH