A University of Texas-Southwestern Medical Center study indicates that women diagnosed with subclinical hypothyroidism during pregnancy appear to be at increased risk for severe preeclampsia when compared with women who have normal thyroid function. In hyperthyroid, normal thyroid, and subclinical hypothyroid groups, overall incidences of hypertension during pregnancy were 6.2%, 8.5%, and 10.9%, respectively. After adjusting for confounding factors, significant association was observed between subclinical hypothyroidism and severe preeclampsia.

Abstract: Obstetrics & Gynecology, February 2012.