Overt and subclinical thyroid dysfunction among Indian pregnant women and its effect on maternal and fetal outcome

Thyroid disorders are among the common endocrine problems in pregnant women. It is now well established that not only overt, but subclinical thyroid dysfunction also has adverse effects on maternal and fetal outcome. There are few data from India about the prevalence of thyroid dysfunction in pregnancy. With this background, this study aims to find prevalence of thyroid dysfunction in pregnancy and its impact on obstetrical outcome in Indian population.

Six hundred and 33 pregnant women in second trimester were registered. Detailed history and examination was done. Apart from routine obstetrical investigations, TSH level estimation was done. If TSH level was deranged then free T4 and thyroperoxidase antibody level estimation were done. Patients were managed accordingly and followed till delivery. Their obstetrical and perinatal outcomes were noted.

Prevalence of thyroid dysfunction was high in this study, with subclinical hypothyroidism in 6.47% and overt hypothyroidism in 4.58% women. Overt hypothyroids were prone to have pregnancy-induced hypertension (P=0.04), intrauterine growth restriction (P=0.01) and intrauterine demise (P=0.0004) as compared to control. Cesarean section rate for fetal distress was significantly higher among pregnant subclinical hypothyroid women (P=0.04). Neonatal complications and gestational diabetes were significantly more in overt hyperthyroidism group (P=0.03 and P=0.04, respectively).

Prevalence of thyroid disorders, especially overt and subclinical hypothyroidism (6.47%) was high. Significant adverse effects on maternal and fetal outcome were seen emphasizing the importance of routine antenatal thyroid screening.