Effect of homocysteine concentration in early pregnancy on gestational hypertensive disorders and other pregnancy outcomes.

BACKGROUND Increased total homocysteine (tHcy) may be associated with placental-mediated adverse pregnancy outcomes, but few prospective studies have measured tHcy before pregnancy outcome. This study was undertaken to determine whether increased tHcy measured in early pregnancy is associated with pregnancy loss, gestational hypertension (GH), preeclampsia, or small for gestational age (SGA) infants. METHODS We conducted a prospective cohort study between 2002 and 2005. We measured tHcy and serum folate in blood samples from pregnant women (<20 weeks' gestation) and collected detailed pregnancy information through a questionnaire and medical record review. RESULTS Of the 2119 women included in the study, 103 had a pregnancy loss, 115 had gestational hypertension, 65 had preeclampsia, and 129 had an SGA infant. Subjects with increased tHcy concentrations were at increased risk of pregnancy loss [relative risk (RR) 2.1, 95% CI 1.2-3.6] or preeclampsia (RR 2.7, 95% CI 1.4-5.0) than subjects with lower tHcy concentrations, but increased tHcy concentration was not associated with increased risk of developing GH or having an SGA infant. CONCLUSION The finding of high tHcy in early pregnancy as a risk factor for pregnancy loss and preeclampsia is consistent with a hypothesis that increased tHcy results in abnormalities of the placental vasculature.