Birth asphyxia: experience in Lagos, Nigeria. In Nigeria, at every 20 minutes a child dies from birth asphyxia. This study was conducted to determine the perinatal factors associated with birth asphyxia in a hospital in the western part of Nigeria. Information on maternal and fetal/neonatal conditions were obtained from the case files of all (n=1320) cases of perinatal deaths over a 5-year period (1988-1993). A further search of other case files in the perinatal wards, pathology and autopsy departments identified an additional 52 cases of birth asphyxia that occurred during that period. The perinatal and perinatal asphyxia-related mortality rates in Nigeria are reported. The overall perinatal mortality rate in the hospital was 26.5 per 1000 births; the perinatal asphyxia-related mortality rate was 11.6 per 1000 births. The fetal factors associated with birth asphyxia in this series included prematurity, a birth weight of < 1000 g, and a pregnancy-induced hypertension. The results suggest that intrapartum fetal distress may be responsible for more cases of asphyxia-related perinatal mortality in this hospital than had been expected. Efforts should therefore be made to educate caregivers about intrapartum fetal distress and the need to take appropriate steps to minimize its occurrence.