SEX-RATIOS OF OFFSPRING AND THE CAUSES OF PLACENTAL PATHOLOGY

The sex ratios of offspring associated with various types of placental pathology were studied in order to investigate whether this may throw light on the causes of the pathology, The literature was searched for data on the sex ratios of offspring associated with: abruptio placent a, placenta praevia, placenta accreta, extrauterine pregnancy, acute f atty liver of pregnancy or toxaemia of pregnancy. Highly significant m ale excesses associated with abruptio placenta, placenta praevia, fatt y liver of pregnancy and toxaemia were noted, Highly significant femal e excesses were found to be associated with placenta accreta and extra uterine pregnancy, Each type of pathology is associated with a typical ly biased offspring sex ratio, No explanation of this has ever been of fered, so it seems worth postulating that the abnormal sex ratios are caused by abnormal hormone concentrations at conception, and that thes e are associated with abnormal hormone concentrations later on which a re partially responsible for the pathology, The point could be tested by examining the extent to which hormone concentrations control first, Fallopian tube motility, and second, infiltration by extravillous tro phoblasts into the placental bed.