Ethnic differences in perinatal mortality--a challenge.

The perinatal mortality rates of mothers who delivered at St. Thomas's Hospital from 1969 to 1976 have been examined. The rate in the West Indian population was significant higher than in the United Kingdom white population. The increased West Indian mortality was confined to infants with a birth weight of more than 2.0 kg and a gestational age of more than 37 weeks. The relative risk of perinatal death for West Indian mothers compared with UK white mothers was 1.4 at birth weights of 2.5 kg to 2.9 kg, rising to 4.3 at 4.0 + kg. West Indian perinatal mortality in term babies of normal birth weight was higher in all maternal age and parity groups except parity 3, but the difference was greatest in women aged 30 or over. The African perinatal mortality rate was not significantly greater than the UK white rate although it followed the West Indian trends. Pre-eclampsia and forceps delivery were associated with a greatly increased perinatal mortality in West Indian babies. The excess West Indian mortality could not be explained completely by differences in the proportions of stillbirths and early neonatal deaths nor by the distribution of births by parity, maternal age, or social class. Possible explanations for the differences in mortality are discussed.