The impact of fetal gender on preterm birth in a southern Chinese population.
OBJECTIVE
This study was conducted to determine whether carrying a singleton male fetus increases the risk of preterm birth (PTB) in Chinese women.


METHODS
A retrospective cohort study was conducted on women with singleton pregnancies and delivered in our hospital. Maternal characteristics, pregnancy outcome, and incidence of PTB, were compared between women carrying a male versus a female fetus. The independent effect of a male fetus on PTB was examined with multiple logistic regression analysis adjusting for the other confounding factors identified.


RESULTS
There were significant differences in maternal and infant characteristics between women with a male versus a female fetus. Despite similar or lower incidences of complications and labor induction, women with a male fetus had increased birth <37 weeks (7.0% versus 6.2%, p<?0.001) and birth at 34?36 weeks (5.15% versus 4.4%, p<0.001), but not for birth <34 weeks (2.0% versus 1.8%, p=?0.163). Regression analysis confirmed the association between male fetus with birth at 34-36 weeks (aOR 1.11, 95% CI 1.10?1.33) and spontaneous preterm labor (aOR 1.09, 95% CI 1.00-1.19).


CONCLUSIONS
The results confirmed that carrying a male fetus is an independent risk factor for spontaneous preterm labor and PTB at 34?36 weeks gestation in southern Chinese women.
Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, PRC. lao-tt@cuhk.edu.hk
Terence T
TT
Lao
Daljit S
DS
Sahota
Stephen S H
SS
Suen
Lai Wa
LW
Law
D000328:Adult; D017677:Age Distribution; D044466:Asian People / Q000706:statistics & numerical data; D002681:China / Q000453:epidemiology; D005260:Female; D005333:Fetus / Q000502:physiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008423:Maternal Age; D007744:Obstetric Labor Complications / Q000453:epidemiology; D011153:Population; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology*; D012307:Risk Factors; D012727:Sex Characteristics; D055815:Young Adult