Reproductive Health (Oct 2016)
Prevalence and risk factors related to preterm birth in Brazil
Abstract
Abstract Background The rate of preterm birth has been increasing worldwide, including in Brazil. This constitutes a significant public health challenge because of the higher levels of morbidity and mortality and long-term health effects associated with preterm birth. This study describes and quantifies factors affecting spontaneous and provider-initiated preterm birth in Brazil. Methods Data are from the 2011–2012 “Birth in Brazil” study, which used a national population-based sample of 23,940 women. We analyzed the variables following a three-level hierarchical methodology. For each level, we performed non-conditional multiple logistic regression for both spontaneous and provider-initiated preterm birth. Results The rate of preterm birth was 11.5 %, (95 % confidence 10.3 % to 12.9 %) 60.7 % spontaneous - with spontaneous onset of labor or premature preterm rupture of membranes - and 39.3 % provider-initiated, with more than 90 % of the last group being pre-labor cesarean deliveries. Socio-demographic factors associated with spontaneous preterm birth were adolescent pregnancy, low total years of schooling, and inadequate prenatal care. Other risk factors were previous preterm birth (OR 3.74; 95 % CI 2.92–4.79), multiple pregnancy (OR 16.42; 95 % CI 10.56–25.53), abruptio placentae (OR 2.38; 95 % CI 1.27–4.47) and infections (OR 4.89; 95 % CI 1.72–13.88). In contrast, provider-initiated preterm birth was associated with private childbirth healthcare (OR 1.47; 95 % CI 1.09–1.97), advanced-age pregnancy (OR 1.27; 95 % CI 1.01–1.59), two or more prior cesarean deliveries (OR 1.64; 95 % CI 1.19–2.26), multiple pregnancy (OR 20.29; 95 % CI 12.58–32.72) and any maternal or fetal pathology (OR 6.84; 95 % CI 5.56–8.42). Conclusion The high proportion of provider-initiated preterm birth and its association with prior cesarean deliveries and all of the studied maternal/fetal pathologies suggest that a reduction of this type of prematurity may be possible. The association of spontaneous preterm birth with socially-disadvantaged groups reaffirms that the reduction of social and health inequalities should continue to be a national priority.
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