Perinatal mortality among twins and singletons in a city in southeastern Brazil, 1984-1996

Analysis of 116,699 deliveries (1062 twin pairs and 115,637 singletons) whi ch occurred from 1984 to 1996 at the largest obstetric center in Campinas, SP, Brazil, provided the following conclusions: 1) despite the low percenta ge of twin births (0.9%), 10.7% of all early neonatal deaths and 3.5% of al l stillbirths were twins. Compared to singletons, the likelihood of stillbi rths and early neonatal deaths among twins was 1.9 and 6.5 times greater, r espectively. 2) The proportion of twins among early neonatal deaths tended to decrease, probably because of improvements in prenatal and perinatal car e. 3) The critical period for early neonatal deaths in singletons and twins lasted fur the three first days after birth. 4) The incidence of perinatal deaths among twins was highest among MM pairs, followed by FF pairs, and l owest among MF pairs. 5) There was a trend towards a decrease in the annual rate of early neonatal deaths among both singletons and twins, and of stil lbirths among singletons, the latter being more conspicuous among females. 6) The sex ratio of singletons was practically stable among living newborns , but showed strong cyclic variation among early neonatal deaths, and a ten dency to increase among stillbirths. Twins who died in the first week, as w ell as living twins showed a strong increase in their sex ratio from 1984 t o 1996. 7) The mean gestational age of singletons was highest among living newborns followed by stillbirths, and was lowest among early neonatal death s. The mean gestational age of living twins was higher than that of early n eonatal deaths, but not different from that of stillbirths. 8) The mean bir th weight of singletons and twins was highest among living newborns, follow ed by stillbirths, and lowest among early neonatal deaths. 9) Apgar scores greater than or equal to 7 obtained five minutes after birth are inadequate as a reliable indicator of the clinical condition of the newborn, since al most half of the early neonatal deaths had 5-min Apgar scores varying from 7 to 10.