Obstetric and Neonatal Outcomes in Pregnant Women With Hypothyroidism: A Case–Control Study

Background: Hypothyroidism in pregnancy can have adverse obstetric and neonatal outcomes, depending on the severity of the biochemical abnormalities. Aim: To estimate the prevalence of hypothyroidism in pregnant women and analyze the obstetric and neonatal outcomes (including structural fetal anomalies) in pregnancies with maternal hypothyroidism Materials and Methods: This retrospective study was conducted using data of pregnant women who were consulting at Royal Hospital (Muscat, Oman) from January 2012 to December 2014. A total of 191 pregnant women with singleton pregnancies who had hypothyroidism and no other comorbidities were considered the study group, and 191 women with normal thyroid levels and no other comorbidities were considered the control group. Obstetric complications, neonatal outcomes, and structural fetal anomalies were compared between the 2 groups. Results: The prevalence of hypothyroidism in pregnancy was 2.26%. The rate of cesarean deliveries was 29.6% in the study group, compared with 23% in the control group. The rate of miscarriages in the study group was 5.3%, compared with none in the control group (P =.002). Obstetric complications such as atonic postpartum hemorrhage were significantly high among women in the study group (10%; P =.001). The incidence of low birth weight (< 2 kg at term) was 8.3% in the study group, compared with 2% in the control group (P =.019). In the study group, the rate of structural fetal anomalies was 11%, compared with 4% in the control group (P =.002). The rate of prematurity was also significantly high in the study group (5.2%; P =.002). Conclusion: Hypothyroidism in pregnancy carries a higher risk of obstetric and neonatal complications and structural fetal anomalies.