Maternal risk factors associated to stillbirth in a public hospital at West of Mexico [Factores de riesgo materno asociados a muerte fetal en nacimientos pretérmino en un hospital público del occidente de México]

Abstract

Introduction. Mortality rates in preterm births and stillbirth are high. Objective. To identify maternal risk factors relating to stillbirth in preterm infants. Material and methods. We conducted a cross-sectional, analytic study of 1,022 newborns between 20 and 36 weeks of gestation, from September 2004 to August 2005. Stillbirth was defined as fetal death prior to expulsion or extraction from the mother. Data was collected prospectively by directly interviewing the pregnant women and from the medical chart. The dependent variable was stillbirth and the independent ones were the maternal risk factors. Associations were evaluated by logistic regression. Results. One thousand and twenty-four (1,024) preterm births were detected in a total of 14,882 births (6.9%/year). One hundred and fifty-two (152) were stillborn and 870 were live births. The fetal mortality rate was 10.3 per 1,000 live births. The least common maternal factors associated to stillbirth included: urinary tract infection (22/152, 14% vs. 224/869, 26%, p = 0.020), PMR > 24 h (18/152, 12% vs. 172/869, 20%, p = 0.020) and cesarean delivery (24/138, 17% vs. 344/719, 48%, p < 0.001). The crude odd risk ratios for stillbirth included spontaneous preterm delivery (OR 4.38, CI95% 2.70-7.17) and deficient prenatal care (OR 2.64, CI95% 1.83-3.82). By multivariate analysis, stillbirth predictors included: spontaneous preterm delivery (OR 4.00, CI95% 2.61-6.61) and deficient prenatal care (OR 2.54, CI95% 1.78-3.62). Conclusion. Deficient prenatal care was the only statistically significant and clinically coherent variable predicting stillbirth.