title: Male predominance in fetal distress during labor.
abstract: OBJECTIVE
  The purpose of this study was to assess the association between fetal sex and the occurrence of fetal distress during labor.
  
  
  METHODS
  This was a prospective cohort study that incorporated data about 423,033 singleton pregnancies from the national perinatal database for secondary obstetric care in The Netherlands. All singleton pregnancies on record that were delivered under the responsibility of obstetricians in The Netherlands between January 1, 1990, and December 31, 1994, were analyzed. Data about fetal sex, gestational age at delivery, birth weight, fetal distress during labor, mode of delivery, signs of asphyxia at birth, and perinatal death were collected. The associations between sex and the occurrence of operative delivery for fetal distress, low 5-minute Apgar score (score, 0-3), and perinatal death were evaluated by logistic regression analysis.
  
  
  RESULTS
  Male fetuses are at increased risk for fetal distress during labor, for low Apgar scores, and for perinatal death. After adjustment for fetal birth weight and gestational age at delivery, the odds ratios were 1.48, 1.27, and 1.27, respectively. All three associations were highly statistically significant (P <.0001).
  
  
  CONCLUSIONS
  Male fetuses are at increased risk during labor and delivery.
authors.affiliation: Department of Obstetrics and Gynaecology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands. D.J.Bekedam@olvg.nl
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Bekedam
authors.forename: Simone
authors.initials: S
authors.lastname: Engelsbel
authors.forename: Ben W j
authors.initials: BW
authors.lastname: Mol
authors.forename: Simone E
authors.initials: SE
authors.lastname: Buitendijk
authors.forename: Karin M
authors.initials: KM
authors.lastname: van der Pal-de Bruin
mesh_terms: D001034:Apgar Score; D001238:Asphyxia Neonatorum / Q000453:epidemiology; D001724:Birth Weight; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000379:methods; D005260:Female; D005316:Fetal Distress / Q000453:epidemiology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007743:Labor, Obstetric; D016015:Logistic Models; D008297:Male; D009426:Netherlands; D016017:Odds Ratio; D011247:Pregnancy; D011446:Prospective Studies; D012727:Sex Characteristics