PP076. Gender differences in fetal growth and fetal-placental ratio in preeclamptic and normal pregnancies

Abstract

Boys have higher morbidity and mortality than girls,particularly when born prematurely, despite higher birthweight. Adaptation to poor intrauterine environment by reducing fetal growth is more prevalent in female than male fetuses. Differences in reponses between the genders might be mediated by placental functions, as illustrated by the fetal-placental ratio. To study the fetal-placental ratio in normal and preeclamptic pregnancies and compare this ratio in boys and girls. The STORK study (n=1031) is a prospective, longitudinal study of fetal growth. We calculated fetal-placental ratio for boys and girls in normal and preeclamptic pregnancies. Differences between groups were analysed by independent t-tests. Boys had a higher fetal-placental ratio than girls (5.26 vs 5.1 g, p=0.015) in normal pregnancies. 39 women (3.8%) developed preeclampsia. Boys had the same ratio in both groups. Girls in preeclamptic pregnancies had a lower ratio than in normal pregnancies (4.5 vs 5.1 g, p=0.05). Boys appear to invest more in their own growth than in placental growth. In preeclampsia they maintain the same fetal-placental ratio. In girls, birthweight is lower whereas placental weight is maintained, giving a reduced fetal-placental ratio. This pattern is more pronounced in preeclampsia. #Birthweight according to gestational age * corrected for gestational age.