Publication:

Subclinical hypothyroidism in pregnancy and outcomes

Background Screening for subclinical hypothyroidism is essential in all pregnant women, especially in the Indian context, as Indian women have increased risk of developing iodine deficiency during pregnancy. Hence this study was undertaken to study the prevalence of subclinical hypothyroidism. Emphasis was put to know the need for universal screening and also the obstetric outcome in terms of perinatal morbidity and mortality and maternal morbidity were assessed.

Methods It was a prospective analytical study. Sample size consisted of 200 pregnant women attending antenatal OPD. Thyroid profile (serum TSH, FT3 and FT4) was done during first visit and in subsequent trimester of each pregnant woman. The results were analyzed taking into consideration recent endocrine society guidelines. Patients with normal thyroid levels were taken as controls. Detailed history taken, physical examination and routine laboratory investigations were done. Patients with SCH were started on Levothyroxine and serial monitoring of TSH done until delivery. The patients were followed up to assess the mode of delivery, maternal and fetal outcome and any associated co-morbidities to serve the secondary objective of the study. Babies of SCH mothers were screened as well to rule out congenital hypothyroidism.

Results Incidence of SCH was found to be 9.5% in the patients studied. Pregnant women with SCH had increased risks of developing anemia (31.5%), preeclampsia (15%), GDM (5%) and prematurity (10%), higher cesarean section rate (36.8%). Neonates of women with SCH had higher incidence poor APGAR score (47.36%), LBW (15%), NICU admission (10%), IUGR (5%). Increased maternal age and more BMI were associated with higher incidence of subclinical hypothyroidism.

Conclusions Prevalence of subclinical hypothyroidism among pregnant women is fairly high among Indians. Screening for subclinical hypothyroidism has to be included as a routine screening test and should be treated accordingly to improve maternal and fetal outcomes.