Sociodemographic factors and prenatal care behaviors associated with unplanned pregnancy in a Brazilian birth cohort study

Objective: To identify the sociodemographic factors and prenatal behavior characteristics associated with unplanned pregnancy. Methods: A cross-sectional survey was conducted of mothers of newborns enrolled in a birth cohort in Ribeirão Preto, Brazil. Questionnaires were administered to postpartum women. Multiple logistic regression was used to identify sociodemographic predictors of unplanned pregnancy and to evaluate the association with adherence to prenatal care recommendations. Results: The cohort included 7608 mothers: 7541 (99.1%) answered the interview and 4056 (53.8%) had an unplanned pregnancy. Adolescents were more likely to have an unplanned pregnancy (odds ratio [OR] 1.87; 95% confidence interval [CI] 1.50–2.34) as were women over 40 (OR 1.74; 95% CI 1.22–2.47). Pregnancy during adolescence (OR 1.27; 95% CI 1.09–1.48), being single (OR 7.56; 95% CI 5.98–9.56), having two or more previous births (OR 1.73; 95% CI 1.52–1.97), and being of a lower socioeconomic status were also predictors. Lack or late initiation of prenatal care, attendance at less than six prenatal visits, drinking alcohol, and smoking during pregnancy were associated with unplanned pregnancy. Conclusion: Unplanned pregnancies disproportionately affect women at extremes of age, single, and of low socioeconomic status. These women are less likely to adhere to prenatal care.