Ethnic differences in blood pressure and hypertensive complications during pregnancy: the Generation R study

The aim was to investigate ethnic differences in blood pressure levels in each trimester of pregnancy and the risk of gestational hypertensive disorders and the degree to which such differences can be explained by education and lifestyle-related factors. The study included 6215 women participating in a population-based prospective cohort study from early pregnancy onward in Rotterdam. Ethnicity was assessed at enrollment. Blood pressure was measured in each trimester. Information about gestational hypertensive disorders was available from medical charts. Lifestyle factors included smoking, alcohol, caffeine intake, folic acid supplementation, sodium and energy intake, body mass index, and maternal stress. Associations and explanatory pathways were investigated using linear and logistic regression analysis. Dutch pregnant women had higher systolic blood pressure levels as compared with women in other ethnic groups in each trimester of pregnancy. Compared with Dutch women, Turkish and Moroccan women had lower diastolic blood pressure levels in each trimester. These differences remained after adjusting for education and lifestyle factors. Turkish and Moroccan women had a lower risk of gestational hypertension as compared with Dutch women (odds ratio, 0.32 [95% CI, 0.18-0.58] and odds ratio, 0.28 [95% CI, 0.14-0.58]), and Cape Verdean women had an elevated risk of preeclampsia (odds ratio, 2.22 [95% CI, 1.22-4.07]). Differences could not be explained by education or lifestyle. Substantial ethnic differences were observed in blood pressure levels and risk of gestational hypertensive disorders in each trimester of pregnancy, and a wide range of variables could not explain these differences.