PREGNANCIES COMPLICATED BY RETAINED PLACENTA - SEX-RATIO AND RELATIONTO PREECLAMPSIA

Pre-eclampsia and placenta accreta have opposite histological features of placentation. This study set out to test the hypotheses that the s ex ratios in these two pregnancy complications are opposite and that t hese conditions are mutually exclusive, ii population-based database c overing all deliveries in South Australia between 1986 and 1995 and th e hospital-based obstetric database of the Adelaide Women's and Childr en's Hospital, covering 8549 births between 1993 and 1995, were used t o ascertain the sex ratios in singleton pregnancies and the sex ratios in those pregnancies in which there was retained placenta, hypertensi on in pregnancy, or pre-eclampsia. The likelihood of independence of o ccurrence or mutual exclusivity of retained placenta and hypertension in pregnancy or pre-eclampsia were also examined. The male:female sex ratio in the South Australian population was 1.077. In pregnancies wit h hypertension in pregnancy it was 1.165 (P<0.001) and in pregnancies with retained placenta it was 0.883 (P<0.0001). There was a trend to a n increased sex ratio in pre-eclamptic pregnancy (1.248 in primigravid and 1.092 in multigravid women) but there was insufficient power to d etect significance (P=0.207 and 0.470, respectively). Neither hyperten sion in pregnancy nor pre-eclampsia were mutually exclusive of placent a accreta: hypertensive disorders of pregnancy and placenta accreta oc curred independently of each other. Our findings suggest that sex-link ed antigens are unlikely to influence maternofetal interactions consis tently to give rise to one but not the other pregnancy complication. ( C) 1998 W. B. Saunders Company Ltd.