[Detection of subclinical hypothyroidism in pregnant women with different gestational ages]

To detect subclinical hypothyroidism in pregnant women.

Seventy-five pregnant women who resided in the town of Itabuna, state of Bahia, were voluntarily studied. Inclusion criteria were age < 40 years, no history of previous thyroid disease, autoimmunopathy or diabetes mellitus, and any gestational age; a clinical evaluation (an interview obeying to a questionnaire); laboratory evaluation (free T4, TSH, anti-TPO antibody, total and HDL cholesterol, triglyceride determinations); thyroid ultrasonography.

Average age was 21.6 +/- 5.1 (14-40 years); gestation age was 24.2 +/- 8.2 (5-39 weeks); an elevated TSH with normal free T4 was found in 3 cases (4.0%). Anti-TPO antibodies were positive in 8.0% on the pregnant women. In 5.4% of them, thyroid ultrasonographic changes were documented.

Based on finding of a 4% prevalence of elevated TSH during pregnancy, the authors consider important the inclusion of thyroid function laboratory evaluation in the routine prenatal examination. Further studies appear necessary to establish at what gestational age thyroid function evaluation should be started in pregnant women and how frequently it should be repeated during the course of gestation.