Prevalence and complications of subclinical and overt hypothyroidism in pregnancy at North Indian tertiary care center

Abstract

Background: Thyroid disorders are one of the commonest endocrine problems among pregnant women. It is often argued that it is not only overt, but subclinical thyroid dysfunction also has similar adverse effects on maternal and fetal outcomes. There is a huge deficiency of data from the Indian population to assess the prevalence of thyroid dysfunction in pregnancy. This study aimed to determine the prevalence of thyroid disorders in pregnancy and their impact on obstetrical outcomes in the Indian population. The study also had the objective of finding a correlation between maternal and fetal thyroid-stimulating hormone (TSH) levels in hypothyroid pregnancies. Materials and Methods: Around 1055 pregnant women in the first and second trimesters were enrolled in the study. A detailed history was noted and general examinations were done. Apart from routine obstetrical investigations, TSH level estimation was done. If the TSH level was deranged, then free T4 (fT4) and free T3 (fT3) levels were also estimated. Furthermore, 50 hypothyroid and euthyroid pregnant women from the same cohort were followed till delivery. Their obstetrical and perinatal outcomes were noted. Results: The prevalence of thyroid dysfunction was 36.5% in this study, which was quite high in the population. Moreover, hypothyroid groups were prone to have pregnancy-induced hypertension (P = 0.03), intrauterine growth restriction (P = 0.05), and preterm delivery (P = 0.04) as compared to control. Cesarean section rate for fetal distress was significantly higher among pregnant hypothyroid women (P = 0.05). Neonatal respiratory distress and low appearance, pulse, grimace, activity, and respiration (APGAR) () scores were significantly more in the hyperthyroidism group (P = 0.04 and P = 0.02, respectively). Maternal TSH was significantly correlated with hemoglobin levels, HbA1c, and systolic blood pressure. Conclusions: Significant adverse effects on maternal and fetal outcomes were seen emphasizing the importance of routine antenatal thyroid screening.