The association between stillbirth and fetal gender

Objective. Stillbirth accounts for approximately 50% of all perinatal deaths. We aimed to characterize the relationship between fetal gender and stillbirths. Methods. A retrospective cohort study of all stillbirths cases in a tertiary medical center, between 1995 and 2007. Patient's medical charts were reviewed for demographic information, medical data, and assumed etiology for stillbirth. Stillbirth was defined as fetal death after 20 completed weeks of gestation or birth weight above 500 g, excluding cases of fetal death due to elective termination of pregnancy. Results. Overall, during the study period there were 77,120 deliveries, of them the stillbirth rate was 0.14% (n = 105). There were 59 females, 39 males (60.2% vs. 48.5%, p = 0.04) and 7 cases of stillbirth with undetermined gender. There were no differences in the demographic and obstetrical characteristics at diagnosis between women carrying a male versus female stillbirth fetuses. The rate of intra uterine fetal death due to placental abruption was significantly higher for male fetuses (OR = 2.1, 95% CI 1.3-4.5) and the rate of stillbirth due to placental insufficiency was significantly higher for female fetuses (OR = 3.7, 95% CI 1.6-5.1). Conclusions. Female fetuses are overrepresented in cases of stillbirths compared with male fetuses.