Fatores sociodemográficos, comportamentais, características obstétricas e de assistência à saúde associadas com baixo peso ao nascer: um estudo de caso-controle

Abstract

The objective of this work was to identify the factors associated with a low birth weight (LBW) of newborns treated at hospitals in the Single Health System (SUS). For more than a century, the birth weight has been used as a parameter for health care and infant mortality. The cut of (LBW), of 2,500 grams (g) was described for the first time in 1919, when there wasn’t differentiation between prematurity and LBW. This classification is based on the risk of death increased up to 20 times when compared to babies born with higher weight. Annually around 20 million of babies are born with LBW in Brazil and in the state of Paraná the average rates remains around 9% of births. The LBW is one of the most responsible for child mortality, neonatal death, for the appearance of diseases throughout the baby's life, as well as determining the quality of health care. The LBW is multifactorial character involving behavioral, obstetric and socioeconomic factors. Smoking, as well as obesity and the use of illicit drugs, are presents close relation with the LBW, although it’s factors that can be intervened. On the other hand, favorable sociodemographic factors such as income, pregnant woman age, first pregnancy age, number of pregnancies, education, occupation, marital and social situation, have a strong positive association with the quality of life during pregnancy. Low education represents risks for the mother-fetal binomial, not only when manifested by mother, but also by partner. However, few studies relate paternal influences on outcome at birth. The World Health Assembly specified goals to reduce child mortality, aiming to reduce 4% annually and 30% of LBW until 2025. Method: Community-based case-control study that analyzed data from 78 newborns and their respective mothers, from a total of 409 dyads, users of SUS in the city of Francisco Beltrão (Paraná, Brazil), July 2017 to July 2018. Cases were babies weighing ≤2,500 g and controls> 2,500 g. The babies were matched for sex and date of birth. Results: Strong statistically significant differences in the bivariate analyzes were found, where the number of smokers active or who stopped during pregnancy, as well as users of illicit drugs were significantly higher among mothers of babies in the case group. Gestational week was also significantly shorter in the cases. Logistic regression models indicated that gestational week (OR = 0.04, 95% CI: -5.31, -1.31) and pre-gestational BMI (OR = 0.19; 95% CI: -70.52, -0.20) were related to a lower chance of LBW, while smoking (OR = 3.18; 95% CI: 19.03, 539.30) was associated with higher LBW. Therefore, studies and investigations about LBW are extremely important for the creation of actions and strategies in public health. Even knowing that BPN includes a variety of possibly causal factors, it is understood that most of them are subject to specific interventions and preventive in order to minimize LBW and thus promote health as a whole.