title: Sex ratio at birth in Zaria, Nigeria.
abstract: OBJECTIVE
  The objectives of this study were to determine the sex ratio at birth in Ahmadu Bello University Teaching Hospital, Zaria, Nigeria and its relationship with certain pathologies including breech presentation, twin delivery, major degree placenta praevia and abruptio placentae.
  
  
  METHODS
  A retrospective analysis of records of all deliveries in the hospital between 1 January 1991 and 31 December 2002 (10 years) was carried out. To minimize bias, breech presentation included singletons only and placenta praevia included only major degrees confirmed at Caesarean section.
  
  
  RESULTS
  The total number of deliveries during the study period was 12 845. The male:female ratio was 1.12. Sex ratio at birth was not significantly associated with any of the conditions studied, although there was a slight male preponderance with placenta praevia (57.3% in babies born to mothers with major degree placenta praevia compared to 52.7% in babies born to mothers without placenta praevia) and first twins (56.3% compared to 52.7% among singletons), and a slight female preponderance with singleton breech presentation (50.9% compared to 47.2% among non-breech deliveries).
  
  
  CONCLUSIONS
  The findings in this study may reflect racial, dietary or environmental variations or a combination of these factors. They may also be as a result of bias from hospital data, emphasizing the need for accurate population-based records of births and other vital statistics.
authors.affiliation: Department of Obstetrics and Gynaecology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria. saasule@yahoo.com
authors.forename: S T
authors.initials: ST
authors.lastname: Sule
authors.forename: H N
authors.initials: HN
authors.lastname: Madugu
mesh_terms: D000037:Abruptio Placentae; D001946:Breech Presentation; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009549:Nigeria; D010923:Placenta Previa; D011247:Pregnancy; D012744:Sex Ratio; D014427:Twins