Northern Ireland twin study 1983.

Two hundred and fifty-three twin deliveries in Northern Ireland during 1983 were studied. A high perinatal mortality rate of 57 per 1000 births was found, over four times greater than the overall perinatal mortality rate for Northern Ireland in that year. The main cause of these losses remains premature delivery which is frequently complicated by fetal growth retardation. Serial ultrasound scanning in the third trimester is considered mandatory in order to reduce the incidence of undiagnosed fetal growth retardation in twins.