Effect of fetal gender on pregnancy outcomes in Northern China.
OBJECTIVE
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.
a Beijing Obstetrics and Gynecology Hospital, Capital Medical University , Beijing , China.
Yajun
Y
Liu
a Beijing Obstetrics and Gynecology Hospital, Capital Medical University , Beijing , China.
Guanghui
G
Li
a Beijing Obstetrics and Gynecology Hospital, Capital Medical University , Beijing , China.
Weiyuan
W
Zhang
D000328:Adult; D017677:Age Distribution; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012737:Sex Factors; D012744:Sex Ratio
Obstetrics complication; perinatal outcome; sex ratio