Contraceptive Use Behavior Change After an Unintended Birth in Colombia and Peru.

Context: No studies using longitudinal contraceptive histories have investigated whether having an unintended birth (i.e., one resulting from an unintended pregnancy) is associated with change in contraceptive behavior, including in Colombia and Peru, where levels of unintended fertility remain high.

Methods: Monthly reproductive history calendar data from the 2010 Colombia and 2012 Peru Demographic and Health Surveys were used to study contraceptive behavior among 13,373 and 7,425 women, respectively. Transition matrices and hazard models were utilized to identify associations between prepregnancy and postpartum contraceptive methods used, and to assess how these relationships differed between women who reported an unintended birth and those with an intended birth.

Results: Women who had been using a traditional, barrier or (in Colombia) short-acting hormonal method before pregnancy were more likely to choose a more effective method postpartum, than to use no method, if their birth had been unintended rather than intended (relative risk ratios, 1.2-1.3 in Colombia; 1.6 in Peru). Compared with their counterparts whose birth had been intended, women with an unintended birth who had been utilizing the most effective methods used in the country (IUD or implant in Colombia, pill or injectable in Peru) were less likely to resume using them postpartum than to use no method (0.7 in Colombia; 0.8 in Peru).

Conclusions: Unintended birth is associated with change in contraceptive behavior. Efforts to understand postpartum contraceptive choices of women who have had an unintended birth should take into account contraceptive behavior at more than one point in women's reproductive lives.