Sex ratios in the families of women ascertained by a toxaemic pregnancy.

Abstract

Preeclampsia/eclampsia are associated with male fetuses but no one has identified a reason for this association. A professor at University College London in England has postulated that parental hormone levels at the time of conception partially controls the sex of the fetus. For example high estrogen levels are linked to subsequent male births. He further hypothesized in 1987 based on the facts that smoking protects against preeclampsia/eclampsia and that smoking has an antiestrogenic effect that high maternal estrogen levels are associated with preeclampsia/eclampsia. But he later learned in 1992 that low maternal estrogen levels are associated with preeclampsia/eclampsia is distinct from the cause for the high sex ratio of associated infants. The next logical consideration is whether male fetuses are somewhat more likely to make their mothers susceptible to preeclampsia/eclampsia. At this point we can ask ourselves 2 questions. Do mothers with male pregnancies have low estrogen levels? If so this would explain the link between preeclampsia/eclampsia and male pregnancies. Do women with preeclampsia/eclampsia in one pregnancy have a disproportionately higher number of daughters in other pregnancies? If so this would support the finding of Arngrimsson et al. that daughters of women who had preeclampsia/eclampsia have a low male/female sex ratio.