Subclinical hypothyroidism and autoimmune thyroiditis in pregnancy--a study in south Indian subjects

To analyse the prevalence of subclinical hypothyroidism among pregnant women attending Government hospitals in South India. It is also aimed to identify the prevalence of thyroid autoimmunity in euthyroid pregnant women.

Five hundred pregnant women attending two government Obstetric and Gynecology hospitals in Chennai during a period of 5 months in 2007, were studied. Excluding subjects with known thyroid diseases, 495 subjects were examined. Detailed physical examination was done and details of pregnancy were recorded. All were subjected to blood tests for Free T4, TSH and TPO antibodies.

Subclinical hypothyroidism was detected in 2.8%, among them TPO antibodies positivity was seen in 57.1% whereas euthyroid women had significantly lower positivity (7%). No association was seen between hypothyroidism or TPO antibody positivity with gestational age or parity. Hypothyroidism diagnosed by elevated TSH value (> or = 5.0 mg/l) was significantly associated with increasing gestational age (Trend chi2 = 6.02, p = 0.014).

Prevalence of subclinical hypothyroidism among pregnant women is fairly high among Indians and they have high rates of TPO antibody positivity. Screening for hypothyroidism has to be included as a routine screening test to improve maternal and foetal outcomes.