Background: The prevalence of obesity in school children and pregnant women, a known risk factor of the reproductive cycle, has increased significantly over the last few years.
Aim: To analyze the association between maternal obesity and the outcome of pregnancy and newborn health. To quantify the attributable population risk of obesity in relation to negative events of pregnancy.
Material and methods: A prospective study in 883 pregnant women of 6 public health centers in Santiago. Weight, height, arm circumference, skinfold thicknesses, body mass index (BMI) and fat mass were determined in each trimester. Maternal socio demographic history, smoking habits, incidence of diseases during pregnancy, labor and newborn characteristics were analyzed. Logistic regressions of multiple factors were used to determine nutritional and non-nutritional variables associated to negative events, to determine the population attributable risk of each variable that the model retained.
Results: Controlling the effect of other variables, a BMI > or = 30 or initial body fat mass > or = 35% determined a greater risk for assisted labor with an odds ratio (OR) of 1.9 (95% confidence interval (CI) 1.3-2.9), gestational diabetes with an OR of 6.4 (95% CI 2.1-19.6), hypertension with an OR of 7.8 (95% CI 3.0-20.4), late fetal mortality with an OR of 3.4 (95% CI 1.2-10.0), p < 0.001. The risk was mostly associated with the initial maternal nutritional status and in a lesser degree, with the weight gained during pregnancy.
Conclusions: Maternal obesity is an important risk factor during pregnancy. The prenatal control obesity could reduce approximately 10% of the cesarean sections and late fetal deaths and half of the hypertension and gestational diabetes cases.