ASSOCIATION OF MATERNAL SUBCLINICAL HYPOTHYROIDISM AND LOW BIRTH WEIGHT AMONG PREGNANT WOMEN ADMITTED FOR DELIVERY AT A TERTIARY CARE HOSPITAL IN KARACHI

Abstract

Background: Maternal thyroid function is important for fetal growth and development, while low birth weight (LBW) is associated with adverse neonatal and later-life outcomes. The relationship between maternal subclinical hypothyroidism (SCH) and LBW remains inconsistent across studies. Objective: To determine the frequency of SCH among pregnant women admitted for delivery and compare the frequency of LBW among women with and without SCH. Methods: A descriptive cross-sectional study was conducted in the Department of Gynecology, Memon Medical Institute Hospital, Karachi, from 15 November 2022 to 30 August 2023. A total of 164 pregnant women aged 15–49 years, admitted for delivery and with gestational age >28 weeks, were enrolled through non probability consecutive sampling. SCH was defined as TSH >5 IU/mL with normal T3 and T4. LBW was defined as birth weight <2.5 kg. Associations were assessed using chi-square/Fisher exact tests, with p<0.05 considered statistically significant. Results: SCH was identified in 24/164 (14.6%) women, while LBW occurred in 43/164 (26.2%) neonates. LBW was observed in 15/24 (62.5%) women with SCH compared with 28/140 (20.0%) women without SCH (reported p=0.00; conventionally expressed as p<0.001). From the reported 2×2 table, the risk ratio for LBW was 3.13 (95% CI 1.99–4.92) and the odds ratio was 6.67 (95% CI 2.65–16.80). Conclusion: SCH was relatively frequent in this hospital-based sample and was associated with a substantially higher frequency of LBW. Further prospective and adequately powered studies are needed to clarify the relationship and its clinical implications.