Comparative study of feto-maternal outcome in clinical and subclinical hypothyroidism

Background: Thyroid diseases are the one of commonest endocrine disorders affecting women of reproductive age group, and hence constitute the commonest endocrine disorder complicating pregnancy. Maternal thyroid function changes during pregnancy and inadequate adaptation to these changes results in thyroid dysfunction. The objective of this study was to determine the prevalence of clinical and subclinical hypothyroidism and to study the fetal and maternal complications associated with hypothyroidism.Methods: A prospective and observational study undertaken over a period of 2 years from 1st October 2009 onwards. Pregnant women were screened for thyroid dysfunction irrespective of gestational age. Patients were divided into two group; Group I (subclinical hypothyroidism)- all pregnant patients with serum TSH ≥ 3 mu/l up to 6 mu/l and normal free T4 levels. Group II (clinical hypothyroidism)- all pregnant patients with serum TSH level ≥ 6 mu/l OR on thyroxine pre-pregnancy.Results: In the present study, prevalence of thyroid disorder was 6.22%, subclinical hypothyroidism and clinical hypothyroidism being 3.77% and 2.45% respectively. In subclinical group and clinical group, we found, preeclampsia, preterm labour, first trimester abortions and oligohydramnios in 13.75% versus 19.23%, 13.75% versus 36.54%, 11.25% versus 11.53%, and 16.25% versus 23.02% respectively. Subclinical hypothyroidism was more prevalent and hidden leading to the poor obstetrical outcome and fetal complications like low birth weight, prematurity and intrauterine growth restriction. There was higher incidence of caesarean deliveries in both groups more in clinical hypothyroid cases.Conclusions: Due to the adverse effect of maternal thyroid disorder on maternal and fetal outcome, timely diagnosis and initiation of treatment of hypothyroid disorders is essential