methimazole and Premature-Birth

Hyperthyroidism can occur during pregnancy and the postpartum period, and the treatment of hyperthyroidism should be considered in the preconception phase. Pregnancy has multiple normal physiologic effects on thyroid hormone, which is a separate process distinct from syndromes such as transient hyperthyroidism of hyperemesis gravidarum. The rationale regarding antithyroid drug use during different stages of pregnancy is reviewed, including the literature regarding adverse neonatal outcomes such as aplasia cutis and methimazole embryopathy in the setting of first trimester maternal methimazole use. The use of treatment modalities for hyperthyroidism during pregnancy such as surgery is also discussed. Studies of maternal, fetal, and neonatal complications of hyperthyroidism are examined in this article. Moreover, the evidence regarding antithyroid drugs, specifically methimazole and propylthiouracil, during lactation is considered. Other disease conditions that can take place during pregnancy and the postpartum period such as hyperemesis gravidarum, subclinical hyperthyroidism, gestational trophoblastic disease, and postpartum thyroiditis and their treatments are also presented.

Topics: Antithyroid Agents; Birth Weight; Female; Humans; Hyperthyroidism; Infant, Newborn; Methimazole; Postpartum Period; Preconception Care; Pregnancy; Pregnancy Complications; Premature Birth; Propylthiouracil; Risk; Thyroid Hormones

Increasing attention has focused on the prevalence and outcomes of hyperthyroidism in pregnancy, given concerns for hepatotoxicity and embryopathy associated with antithyroid drugs (ATDs).. In an integrated health care delivery system, we examined the prevalence of thyrotoxicosis and gestational ATD use (propylthiouracil [PTU] or methimazole [MMI]) in women with delivered pregnancies from 1996 to 2010. Birth outcomes were compared among all infants and those born to mothers with diagnosed thyrotoxicosis or ATD therapy during gestation, with examination of ATD-associated hepatotoxicity and congenital malformations in the latter subgroups.. Among 453,586 mother-infant pairs (maternal age 29.7±6.0 years, 57.1% nonwhite), 3.77 per 1000 women had diagnosed thyrotoxicosis and 1.29 per 1000 had gestational ATD exposure (86.5% PTU, 5.1% MMI, 8.4% both). Maternal PTU-associated hepatotoxicity occurred with a frequency of 1.80 per 1000 pregnancies. Infants of mothers with diagnosed thyrotoxicosis (odds ratio [OR] 1.28, 95% confidence interval [CI 1.05-1.55]) or gestational ATD use (OR 1.31 [1.00-1.72]) had an increased risk of preterm birth compared to those born to mothers without thyrotoxicosis or ATD. The risk of neonatal intensive care unit (NICU) admission was also higher with maternal thyrotoxicosis (OR 1.30 [1.07-1.59]) and ATD exposure (OR 1.64 [CI 1.26-2.13]), adjusting for prematurity. Congenital malformation rates were low and similar among infants born to mothers with thyrotoxicosis or ATD exposure (30-44 per 1000 infants).. Gestational ATD exposure occurred in 1.29 per 1000 mother-infant pairs while a much larger number had maternal diagnosed thyrotoxicosis but no drug exposure during pregnancy. Infants of mothers with gestational ATD use or diagnosed thyrotoxicosis were more likely to be preterm and admitted to the NICU. The rates of congenital malformation were low for mothers diagnosed with thyrotoxicosis and did not differ by ATD use. Among women with gestational PTU therapy, the frequency of PTU-associated hepatotoxicity was 1.8 per 1000 delivered pregnancies. These findings from a large, population-based cohort provide generalizable estimates of maternal and infant risks associated with maternal thyrotoxicosis and related pharmacotherapy.

Topics: Adult; Antithyroid Agents; Chemical and Drug Induced Liver Injury; Cohort Studies; Congenital Abnormalities; Delivery of Health Care, Integrated; Female; Humans; Infant, Newborn; Intensive Care Units, Neonatal; Methimazole; Pregnancy; Pregnancy Complications; Premature Birth; Prevalence; Propylthiouracil; Thyrotoxicosis; Young Adult

To compare, using two large nationwide population-based data sets, the risk of adverse pregnancy outcomes (low birthweight [LBW], preterm birth, small for gestational age [SGA] and congenital anomalies) among pregnant women with hyperthyroidism classified into three groups: receiving propylthiouracil (PTU) treatment during pregnancy, receiving methimazole/carbimazole (MMI) treatment, and no antithyroid treatment during pregnancy.. A matched case-control study.. Taiwan.. A total of 2830 mothers with hyperthyroidism and 14,150 age-matched randomly selected mothers without hyperthyroidism were included.. Conditional logistic regression analyses were performed to examine the risk of adverse pregnancy outcomes (LBW, preterm birth, SGA and major congenital anomalies) among these three groups.. LBW, preterm birth, SGA and major congenital anomalies.. Women receiving PTU treatment during pregnancy had a higher risk of giving birth to LBW infants than those not receiving antithyroid treatment (odds ratio = 1.40; 95% CI 1.00-1.96), after adjusting for maternal education, anaemia, hyperlipidaemia, pregestational diabetes, pregestational hypertension, hyperemesis gravidarum and infant's gender and birth order. However, children of women receiving MMI treatment did not have increased risks of any adverse fetal outcome relative to mothers not receiving antithyroid treatment.. Our study finds an increased risk of LBW among babies of mothers with hyperthyroidism receiving PTU treatment during pregnancy relative to untreated mothers with hyperthyroidism.

Topics: Adult; Antithyroid Agents; Carbimazole; Case-Control Studies; Congenital Abnormalities; Female; Humans; Hyperthyroidism; Infant, Low Birth Weight; Infant, Newborn; Infant, Small for Gestational Age; Logistic Models; Male; Methimazole; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Premature Birth; Prevalence; Propylthiouracil; Taiwan; Young Adult