RESUMEN
OBJECTIVE: To estimate the perinatal mortality rates over a 35 year period in neonates 22 weeks' gestation or above 500 g at birth until seven days postdelivery. METHODS: Data was obtained from medical records and the fetal death (FD) and neonatal death (ND) certificates. RESULTS: There were 889 282 deliveries (D) with 10,178 FD (11.2/1000 D) and 10,126 ND [11.3/1000 live newborns (LNB) with a significant reduction from 1972 to 2006 of 57 % in fetal mortality rate (p <0.0001) and 18.8 % in neonatal mortality rate (p <0.01). We registered 8081/10,126 (79.84 %) neonates who died from 0 to 6 days (9.2/1000 LNB). The overall perinatal mortality rate was 20.5/1000 D, with a 48.4 % significant reduction from 1972 to 2006 (p < 0.0001), 27.8/1000 ND, a 13.5/1000 ND respectively. We observed 4161 immature neonates (0.47 %); 55,340 premature newborns (6.2 %) and 9055 twin pregnancies (1 %). CONCLUSIONS: The fetal, neonatal and perinatal mortality rates were below the national media and presented a significant decrease from 1972 to 2006, more accentuated in fetal mortality rate (57 %) and perinatal mortality rate (48.4 %).