Effect of fetal gender on pregnancy outcomes in Northern China

Purpose: Several studies have demonstrated that fetal gender has a significant effect on the pregnancy outcomes and pregnancy-related complications. However, results differ as the race and population changes. The aim of our study was to test whether the recorded phenomenon of adverse pregnancy outcomes associated with a male fetus applies to women in northern China. Methods: This was a multi-centered, cross-sectional study. The study population included women who delivered babies in 25 different hospitals in 9 provinces in northern China, from 1 January 2011 to 31 December 2011. For our analysis, we selected 65173 singleton birth deliveries at or after 28 weeks that occurred during the year 2011. Results: Male fetal gender was associated with an increased incidence of preterm delivery (8.33% for males; 7.19% for females), gestational diabetes mellitus (4.58% for males; 4.26% for females), fetal macrosomia (9.41% versus 5.78%), lower Apgar score (2.05% versus 1.78%), perinatal death (0.92% versus 0.76%), placenta previa (0.95% versus 0.81%), increased cesarean section delivery (54.87% versus 52.31%) and operative delivery (1.34% versus 1.19%) (p < 0.05). However, female fetuses were associated with an increased risk of preeclampsia at an advanced gestational age (15.86% for males; 17.53% for females), fetal growth restriction (0.74% for males; 1.09% for females), malpresentation (3.6% for males; 4.31% for females), postpartum hemorrhage (2.92% for males; 3.19% for females) (p < 0.05). Conclusions: The recorded phenomenon of adverse pregnancy outcomes associated with a male fetus applies to our population regardless of some different results.