title: PP047. Fetal gender specific differences in markers of placentation and maternal adaptation to pregnancy - The generation R study.
abstract: BACKGROUND
  Evidence indicates a gender specific interaction between the mother, placenta and fetus in which maternal adaptation to pregnancy and outcome partly depends on fetal gender.
  
  
  OBJECTIVE
  This study assesses fetal gender specific differences in placental biomarkers and uteroplacental vascular resistance. Methods Within the Generation R Study, in 1st and 2nd trimester (median 13.3 and 20.4 wks) blood samples were drawn to assess soluble fms-like tyrosine kinase (s-Flt1), placental growth factor (PLGF) and plasminogen activator inhibitor 2 (PAI-2). Uteroplacental resistance was assessed by mean pulsatility index (PI) of the uterine and umbilical arteries in the 2nd trimester. Mann-Whitney U and Student's t-test were performed to assess associations of gender on the above mentioned factors.
  
  
  RESULTS
  In total 8631 women were included (4274 female and 4357 male fetuses). From these women, 172 had a pregnancy complicated by pre-eclampsia (1.9%). Fetal sex related differences in placental biomarkers, being most pronounced in non pre-eclamptic pregnancies (Table 1). Differences were also observed between early (<34wks) and late onset pre-eclamptic women (>34wks).
  
  
  CONCLUSIONS
  This study shows that maternal adaptation to pregnancy varies by fetal gender, suggesting gender specific differences in placentation and placental function. The differences between pre-eclamptic and non pre-eclamptic women, and among pre-eclamptic women, suggest that different mechanisms apply to pre-eclamptic pregnancies.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Brown
authors.forename: Sarah
authors.initials: S
authors.lastname: Timmermans
authors.forename: Eric
authors.initials: E
authors.lastname: Steegers