Four hundred and thirty four twins occurring in 220 women were studied during a period of 11 years (1969–1979) at Notre-Dame Hospital.Perinatal mortality (< 28 days) was compared before and after 1974, and the impact of ultrasound technique upon perinatal outcome was assessed during the second period (1974–1979). The main factor associated with perinatal mortality was low birth weight caused by either prematurity or intrauterine growth retardation.While fetal mortality remained unchanged within the two study periods, neonatal mortality decreased from 68.2/1,000 to 28.9/1,000 mainly due to increased survival rate of twins below 1,500 g at birth.With identical perinatal care during the same period, perinatal mortality and incidence of intrauterine growth-retarded twins remained unchanged despite early diagnosis by ultrasound.
