title: Twin delivery: comparison of incidence and foetal outcome in two health institutions in Benin City, Nigeria.
abstract: BACKGROUND
  The incidence of twin delivery in Nigeria may have changed, in view of the worldwide increase in the rates of twinning attributed to increasing maternal age and use of fertility therapies.
  
  
  OBJECTIVE
  To determine the current incidence of twin delivery in Benin City and document the foetal outcome in twins.
  
  
  METHODS
  A four-year descriptive (cross-sectional) study of twin deliveries in a Nigerian mission hospital was conducted. The foetal outcome in 115 sets of twin was compared with that of 230 singleton controls.
  
  
  RESULTS
  The current incidence of twin delivery was 25.3 per 1000 deliveries or one in 40 births, representing a reduction by 24.2%. Sex ratio was 0.98 : 1 in favour of females. Seasonal variation was observed in the incidence of twin delivery with a significantly higher incidence in wet than in dry season (p < 0.001). Twin pregnancies are at a significantly higher risk of adverse foetal outcome such as low birth weight (LBW), preterm delivery, birth asphyxia and Caesarean delivery compared to singleton pregnancies (p < 0.001).
  
  
  CONCLUSIONS
  Although the incidence of twin delivery remains high in Benin City, it appears to have dropped. Twin pregnancy is associated with increased risk of adverse foetal outcome.
authors.affiliation: Department of Child Health University of Benin Teaching Hospital PMB 1111, Benin City, Nigeria. alpndiony@yahoo.com
authors.forename: Alphonsus N
authors.initials: AN
authors.lastname: Onyiriuka
mesh_terms: D001238:Asphyxia Neonatorum / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D046689:Fetal Mortality; D016519:Hospitals, Religious; D006801:Humans; D015994:Incidence; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008423:Maternal Age; D009549:Nigeria / Q000453:epidemiology; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D047928:Premature Birth / Q000453:epidemiology; D017678:Sex Distribution; D015996:Survival Rate; D014427:Twins