Pregnancy outcomes and relationship to treatment adequacy in women treated early for congenital hypothyroidism: a longitudinal population-based study.

Abstract

Untreated hypothyroidism is associated with a higher risk of adverse obstetric and neonatal outcomes. Pregnancy complications have yet to be evaluated in patients treated early for congenital hypothyroidism (CH). This study aimed to investigate pregnancy outcomes and their determinants in a population-based registry of young adult women with CH. In total, 1748 subjects were diagnosed with CH in the first 10 years after the introduction of neonatal screening in France; 1158 of these subjects completed a questionnaire on fecundity at a mean age of 25.3 years. We analyzed all declared singleton pregnancies ending after greater than 22 weeks of gestation before the initial survey (n = 207 pregnancies) and in the 3 years following the initial survey (prospective study, n = 174 pregnancies). The reference group comprised 7245 subjects from the French National Perinatal Survey. Pregnancy outcomes. Serum TSH concentrations and thyroid hormone requirements. In both the overall and prospective analyses, CH was associated with gestational hypertension, emergency cesarean delivery, induced labor for vaginal delivery, and prematurity. For the prospective population with CH, the adjusted odds ratios (aOR) (95% confidence interval [CI]) were 2.19 (1.26-3.81), 1.88 (1.17-3.02), 1.58 (1.12-2.24), and 1.85 (1.06-3.25), respectively. TSH concentrations at least 10 mIU/l during the first 3 or 6 months of pregnancy were associated with a higher risk of preterm delivery (aOR, 5.6; 95% CI, 1.6-20.0) and fetal macrosomia (aOR, 4.5; 95% CI, 1.03-20.1), respectively, whereas no such relationship was observed for TSH concentrations of 5.0-9.9 mIU/l. CH may result in adverse pregnancy outcomes. These nationwide data suggest that better thyroid disease management is required, particularly during the first two trimesters of pregnancy, together with vigilant monitoring.