[Confounding effect of prematurity in the neonatal death associated with obstetric maternal morbidity].

BACKGROUND

Prematurity is considered the main factor of neonatal mortality in developed countries (60 to 80% of cases).

OBJECTIVE

To determine if obstetric morbidity and/or prematurity are associated with neonatal death.

PATIENTS AND METHODS

A cohort of 25,365 live newborns since January 1st 2000 to December 31st 2004 was studied. Neonatal mortality was compared according to the number of prenatal visits, single or multifetal pregnancy, the presence or not of preeclampsia/eclampsia, cesarean section or vaginal delivery, and duration of rupture of membranes, stratifying by weeks of gestational age or by preterm and term gestation, as it was convenient. Chi-square test and Odds Ratio (OR) with 95% Confidence Intervals were calculated (CI).

RESULTS

There was not significant statistical difference in neonatal mortality at less number of prenatal visits, between single and twin pregnancies, in the presence of preeclampsia/eclampsia and pregnancies without complications, when they were stratified by group of gestational age. When it was controlled gestational age, malformations and maternal-fetal and obstetrical morbidity, there was not difference in mortality of neonates born vaginally or by cesarean section. It was observed an increased risk or neonatal mortality in preterm neonates with 48 hours or more of rupture of membranes (OR 3.05 CI 95% 1.64-5.66)

CONCLUSIONS

Performing and stratified analysis, prematurity was the factor associated with neonatal mortality, and not the number of prenatal visits, multifetal pregnancy, preeclampsia/eclampsia, or cesarean section. The duration of rupture of membranes is an independent factor of prematurity for neonatal mortality.