International Journal of Clinical Obstetrics and Gynaecology

Objective: To determine the frequency of undiagnosed sub-clinical and overt hypothyroidism among pregnant women in Pakistan and assess associated obstetric characteristics.
Methodology: This prospective, multicenter observational study was conducted from February to October 2024across tertiary care hospitals in Pakistan. A total of 1,200 pregnant women aged 18-45 years, in any trimester, were enrolled. Women with known thyroid disorders, autoimmune conditions, or use of thyroid-affecting medications were excluded. Clinical data were recorded using a structured proforma. Blood samples were analyzed for serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), and thyroid peroxidase antibodies (anti-TPO). Subclinical hypothyroidism (SCH) was defined as TSH 2.5-10 mIU/L with normal FT4; overt hypothyroidism was defined as TSH ? 10 mIU/L or low FT4. Data were analyzed using SPSS v20 with significance set at p<0.05.
Results: The 1,200 participants, the mean age was 27.45±5.15 years and mean gestational age was 25.51±8.72 weeks. Thyroid dysfunction was detected in 12.4% of women, with 9.3% having SCH and 3.1% overt hypothyroidism. A significant positive correlation was observed between TSH and anti-TPO levels (r=0.204, p<0.001). Adverse obstetric outcomes were notable: 29.3% had a history of miscarriage, 6.1% reported intrauterine death, 7.5% neonatal death, and 6% preterm birth. Anti-TPO antibodies were elevated in a proportion of women, even among those who were euthyroid. No significant associations were found between thyroid dysfunction and gestational diabetes, pre-eclampsia, or macrosomia in this cohort.
Conclusion: Subclinical hypothyroidism is a prevalent and frequently undiagnosed condition among pregnant women in Pakistan. Given its potential link with adverse pregnancy outcomes, routine antenatal thyroid screening especially in women with risk factors or high anti-TPO titers should be considered. Larger prospective studies are needed to evaluate the long-term impact of maternal thyroid autoimmunity in euthyroid women.