Sexual origins of placental dysfunction

Severe placental dysfunction is much more common in pregnancies with a male than with a female fetus. Furthermore, the birthweight/placental weight ra tio is increased in these pregnancies, consistent with fetal growth restric tion, acid is higher with a male fetus than with a female fetus. These obse rvations of placental insufficiency may underlie the increased in-utero los s rate of male fetuses.