A Population-Based Study of Factors Associated with Postpartum Contraceptive Use by Birth Interval Length

The purpose of this study was to evaluate factors associated with postpartum contraceptive use among women with short and moderate-to-long birth intervals using population-based data from the Pregnancy Risk Assessment and Monitoring System.

Because only Mississippi and Tennessee include a question about birth interval length on their Pregnancy Risk Assessment and Monitoring System survey, this analysis was limited to women from those states who reported information on this variable (N = 2198). Demographic, lifestyle, and reproductive data, including information on postpartum contraceptive use, were obtained from surveys and birth certificates. Logistic regression was used to obtain odds ratios (ORs) and 95% confidence intervals (CIs).

Nearly 90% of women reported currently using a form of contraception during the postpartum period. In the unadjusted model, among women with short birth intervals, there was no association between alcohol consumption during pregnancy and postpartum contraceptive use (OR 1.03, 95% CI 0.15-7.31); however, smoking during pregnancy was associated with a decreased odds of postpartum contraceptive use (OR 0.70, 95% CI 0.25-1.96). Among women with moderate-to-long birth intervals, alcohol use during pregnancy was associated with a decreased odds (OR 0.71, 95% CI 0.28-1.80) and smoking during pregnancy was associated with an increased odds (OR 1.18, 95% CI 0.60-2.30) of postpartum contraceptive use. Regardless of birth interval length, women with no health insurance had a decreased odds of postpartum contraceptive use when compared with women with health insurance (short birth interval: OR 0.89, 95% CI 0.32-2.49 and moderate-to-long birth interval: OR 0.85, 95% CI 0.52-1.39). Among women with short birth intervals, non-Hispanic black women had a decreased odds of postpartum contraceptive use (OR 0.14, 95% CI 0.03-0.64) and women who were unmarried or had a history of preterm delivery had an increased odds of postpartum contraceptive use (unmarried: OR 5.81, 95% CI 1.26-26.69 and preterm delivery: OR 4.19, 95% CI 1.42-12.37, respectively) after adjustment for confounders. Among women with moderate-to-long birth intervals, individuals who identified as Hispanic/mixed race/other had a statistically significant decreased odds of postpartum contraceptive use after adjustment (OR 0.43, 95% CI 0.18-0.99).

Findings underscore the importance of postpartum medical visits for all women, regardless of birth interval length. Certain groups of women may need additional counseling regarding the importance of using contraceptives to prevent another closely spaced or unintended pregnancy.