Effect of fetal gender on pregnancy outcomes in Northern China

Abstract

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 65 173 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.

• Obstetrics complication
• perinatal outcome
• sex ratio

Declaration of interest

The authors report no conflicts of interest.

The study was funded by the Special Research Fund in Nonprofit Health Care Industry of the People’s Republic of China (Grant no. 201002013 to WYZ) and the Research Fund for High-level Talented Individuals of Beijing Health Bureau (Grant no. 2009-2-11 to WYZ).