Hypothyroidism risk increases in preeclampsia cases

Preeclampsia in nulliparous pregnant women may be linked to increased risk of subclinical hypothyroidism in later stages of pregnancy, and women with a history of preeclampsia may have elevated risk of reduced thyroid function as they age, according to findings from 2 studies.

The Calcium for Pre-eclampsia Prevention (CPP) trial, a nested case-control study, included 141 healthy pregnant nulliparous women (cases) in the United States from 1992 to 1995.

A Norwegian population-based, follow-up postpregnancy study (Nord-Trondelag Health Study) evaluated data from 7,121 women from 1995 to 1997, linking to Norway's medical birth registry and extracting birth data from 1967 or later. Serum measurements in the CPP trial were taken before 21 weeks' gestation (baseline) and after presentation of preeclampsia before delivery. The Nord-Trondelag Health Study also measured serum levels of thyroid-stimulating hormone (TSH).

Further, in the Norwegian study, those with prior history of preeclampsia in a first pregnancy had greater chances of concentrated TSH above reference range (>3.5 mIU/L) compared with women without history of preeclampsia (adjusted odds ratio, 1.7; 95% confidence interval, 1.1-2.5).

Levine RJ, Vatten LJ, Horowitz GL, et al. Pre-eclampsia, soluble fms-like tyrosine kinase 1, and the risk of reduced thyroid function: nested case-control and population based study. BMJ. 2009;339:b4336. doi:10.1136/bmj.b4336.