title: OS036. Ethnic differences in blood pressure and hypertensivecomplications during pregnancy; the generation R Study.
abstract: BACKGROUND
  Blood pressure levels during pregnancy are important risk factors for gestational hypertensive disorders. Non-pregnant women from ethnic minority groups are found to have higher blood pressure levels compared to white women. Little is known about variation in blood pressure development during pregnancy across different ethnic groups.
  
  
  OBJECTIVE
  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.
  
  
  METHODS
  The study included 6215 women participating in a population-based prospective cohort study from early pregnancy onwards in Rotterdam, The Netherlands. Ethnicity was assessed at enrolment. Blood pressure was measured in each trimester. Information about gestational hypertensive disorders was available from medical records. 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.
  
  
  RESULTS
  Dutch pregnant women had higher systolic blood pressure levels as compared to women in other ethnic groups in each trimester of pregnancy. Compared to 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 to Dutch women (OR 0.32; 95% CI: 0.18, 0.58 and OR 0.28; 95% CI: 0.14, 0.58) and Cape Verdean women had an elevated risk of preeclampsia (OR 2.22; 95% CI: 1.22, 4.07). Differences could not be explained by education or lifestyle.
  
  
  CONCLUSIONS
  Substantial ethnic differences were observed in blood pressure levels in each trimester of pregnancy and risk of gestational hypertensive disorders. A wide range of potential explanatory variables could not explain these differences.
authors.affiliation: Generation R Study Group, Erasmus Medical Centre, Rotterdam, Netherlands; Department of Public Health, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: S H
authors.initials: SH
authors.lastname: Bouthoorn
authors.affiliation: Generation R Study Group, Erasmus Medical Centre, Rotterdam, Netherlands; Department of Epidemiology, Erasmus Medical Centre, Rotterdam, Netherlands; Department of Pediatrics, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Gaillard
authors.affiliation: Department of Epidemiology, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Hofman
authors.affiliation: Generation R Study Group, Erasmus Medical Centre, Rotterdam, Netherlands; Department of Epidemiology, Erasmus Medical Centre, Rotterdam, Netherlands; Department of Pediatrics, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: V
authors.initials: V
authors.lastname: Jaddoe
authors.affiliation: Department of Obstetrics and Gynecology, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Steegers
authors.affiliation: Department of Public Health, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: van Lenthe
authors.affiliation: Department of Public Health, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Raat