Prenatal factors and prematurity: retrospective cohort with secondary analysis of data from Birth in Brazil study - Southeast region

Introdução - A prematuridade, definida como nascimento antes de 37 semanas completas de gestação, ainda tem suas vias causais pouco explicadas. Objetivo - Analisar a prevalência de prematuridade e dos fatores do período pré-natal a ela relacionados, por meio de análise secundária dos dados da Região Sudeste, da pesquisa Nascer no Brasil. Métodos - A regressão binária de Poisson foi empregada na seleção das variáveis e as que apresentaram valor de p 35 years-old (RR: 1,28; IC: 1,06 - 1,54); not having a decision for the mode of birth (RR: 1,34; IC: 1,11 - 1,61), >5 antenatal appointments (RR: 2,57; IC: 2,20 - 3,01), >12 prenatal appointments (RR: 0,74; IC: 0,55 - 0,99), maternal black/ brown skin colour (RR: 0,83; IC: 0,73 - 0,95), no previous pregnancies (RR: 1,43; IC: 1,17 - 1,74), previous low birthweight new-born (RR: 1,35; IC: 1,01 - 1,82), previous preterm birth (RR: 2,01; IC: 1,51 - 2,68), previous clinical complications (RR: 1,31; IC: 1,05 - 1,63), obstetric complications in the current pregnancy ((RR: 1,58; IC: 1,18 - 2,12), clinical complications diagnosed at the hospital admission (RR: 1,81; IC: 1,50 - 2,18) and admission at the hospital in the current pregnancy (RR: 2,07; IC: 1,78 - 2,41). Conclusions: Variables identified as protection factors against prematurity were: maternal black or brown skin colour and >12 antenatal appointments. Variables identified as risk factors were: primiparity, maternal age 35, decision for caesarean as the mode of birth, non-participation of the mother in the decision of the mode of birth,