title: Gender does matter in perinatal medicine.
abstract: OBJECTIVE
  To investigate complications and outcome of pregnancies with male and female fetuses.
  
  
  METHODS
  A population-based study comparing all singleton deliveries between the years 1988 and 1999 was performed. We compared pregnancies with male vs. female fetuses. Patients with a previous cesarean section (CS) were excluded from the study. Statistical analyses with the Mantel-Haenszel technique and multiple logistic regression models were performed to control for confounders.
  
  
  RESULTS
  During the study period there were 55,891 deliveries of male and 53,104 deliveries of female neonates. Patients carrying male fetuses had higher rates of gestational diabetes mellitus (OR = 1.1; 95% CI 1.01-1.12; p = 0.012), fetal macrosomia (OR = 2.0; 95% CI 1.8-2.1; p < 0.001), failure to progress during the first and second stages of labor (OR = 1.2; 95% CI 1.1-1.3; p < 0.001 and OR = 1.4; 95% CI 1.3-1.5; p < 0.001, respectively), cord prolapse (OR = 1.3; 95% CI 1.1-1.6; p = 0.014), nuchal cord (OR = 1.2; 95% CI 1.1-1.2; p < 0.001) and true umbilical cord knots (OR = 1.5; 95% CI 1.3-1.7; p < 0.001). Higher rates of CS were found among male compared with female neonates (8.7 vs. 7.9%; OR = 1.1; 95% CI 1.06-1.16; p < 0.001). Using three multivariate logistic regression models and controlling for birth weight and gestational age, male gender was significantly associated with non-reassuring fetal heart rate patterns (OR = 1.5; 95% CI 1.4-1.6; p < 0.001), low Apgar scores at 5 min (OR = 1.5; 95% CI 1.3-1.8; p < 0.001) and CS (OR = 1.2; 95%CI 1.2-1.3; p < 0.001). Controlling for possible confounders like gestational diabetes, cord prolapse, failed induction, nonprogressive labor, fetal macrosomia, nuchal cord and true umbilical cord knots using the Mantel-Haenszel technique did not change the significant association between male gender and CS.
  
  
  CONCLUSIONS
  Male gender is an independent risk factor for adverse pregnancy outcome.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Health Sciences, Soroka University Medical Center, Ben Gurion, Israel. sheiner@bgumail.bgu.ac.il
authors.forename: Eyal
authors.initials: E
authors.lastname: Sheiner
authors.forename: Amalia
authors.initials: A
authors.lastname: Levy
authors.forename: Miriam
authors.initials: M
authors.lastname: Katz
authors.forename: Reli
authors.initials: R
authors.lastname: Hershkovitz
authors.forename: Elad
authors.initials: E
authors.lastname: Leron
authors.forename: Moshe
authors.initials: M
authors.lastname: Mazor
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D005260:Female; D005315:Fetal Diseases / Q000453:epidemiology; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D018743:Perinatal Care / Q000706:statistics & numerical data; D011247:Pregnancy; D012727:Sex Characteristics