[Trends of perinatal mortality at the National Institute of Perinatology].

The purpose of this study is to address the yearly fetal, neonatal, crude death rates observed at the Instituto Nacional de Perinatología from 1987 through 1997, and the specific death rates for birth weight, gestation age, cause of death, avoidability, and structure and process failures as proxy to quality of medical care. Data come from death certificates following the WHO criteria which includes the maternal medical history, pregnancy follow up, birth attendance, newborn characteristics, autopsy findings, microbiological results, basic cause of death (of both maternal and fetal/neonatal origin), death avoidability, and structure and process issues. The death certificates were analyzed by the Perinatal Mortality Committee and registered into a computerized database. The fetal mortality rate during 1987 was 17.67 per 1000 births, whereas in 1997 it was 21.5 per 1000 births. There was an increasing tendency from 1987 to 1992, with the highest rate being 34.13 during 1992. After 1992 this rate shows a decreasing tendency. The neonatal mortality rate decreased from 42.82 in 1987 to 17.34 per 1000 live births in 1997. The highest rates were observed among the newborns with the lowest birth weights and at the youngest gestational ages. The most frequent cause of death of maternal origin, in both fetal and neonatal deaths, was premature rupture of membranes. As for the most frequent fetal cause of death was antepartum hypoxia, and among neonatal deaths prematurity and immaturity. The percentage of avoidable perinatal deaths has declined dramatically from 27% in 1987 to less than 10% in 1996. Perinatal mortality at the Instituto Nacional de Perinatología has decreased during the period under assessment, due to the reduction of the neonatal mortality rate. Improving the quality of medical care focusing mainly on process issues will help lowering avoidable mortality rates.