Observational Study of Subclinical Hypothyroidism in Pregnancy

Maternal thyroid dysfunction is the second common endocrine disorder during pregnancy. Prevalence of subclinical hypothyroidism during pregnancy is increasing. It is associated with adverse maternal and foetal outcomes like pre-eclampsia, GDM, preterm, IUGR and miscarriage, anaemia, IUD.

To study the prevalence of Subclinical hypothyroidism during pregnancy and its relation with adverse maternal and foetal outcomes.

It was an observational study undertaken at RRMCH from May-2013 to Feb 2014. Pregnant women were screened for thyroid dysfunction irrespective of gestational age. Women with raised Thyroid stimulating Hormone (TSH) were included in the study. Pregnancy outcome of women with raised TSH was compared with euthyroid pregnant women.

Study group included 1663 pregnant women. Among them 168 women had hypothyroidism, women with subclinical and overt hypothyroidism were 156 and 12 respectively. Prevalence of hypothyroidism in this study was 10.1%, Subclinical Hypothyroidism and Overt hypothyroidism was 9.3% and 0.72% respectively. Overall prevalence of autoimmunity was 19.04% (n=32) in women with hypothyroidism. Prevalence of autoimmunity in SCH and OH was 17.9% (n=28) and 33.3% (n=4) respectively. In women with SCH 81.4% developed complications like Pre-eclampsia (21.8%), GDM (6.4%), Preterm labor (7.1%) and IUGR (7.7%) anemia (5.8%) compared to euthyroid women (p value <0.001).

Increasing prevalence of Subclinical Hypothyroidism during pregnancy and its association with adverse maternal and foetal outcome makes it a high risk factor. Subclinical hypothyroidism is like the bottom of the iceberg, hence prompt screening for thyroid dysfunction and early initiation of treatment can prevent adverse maternal and fetal morbidity.