A Bridge for postpartum women to Standard Days Method®: I. Developing the Bridge.

BACKGROUND A new fertility-awareness-based Bridge was developed for postpartum women starting with their first postpartum menses and until they are eligible to use the Standard Days Method®. This article describes the development of the Bridge and theoretical efficacy. STUDY DESIGN Analysis of a preexisting data set collected in 1986-1990 was performed. Seventy-three breastfeeding women in Australia, Britain and Canada were followed starting 42 days postpartum until they had at least two potentially fertile cycles. We used these data to calculate the theoretical probability of pregnancy from intercourse on different days of the cycle relative to ovulation for postpartum women following the instructions of the Bridge. RESULTS The fertility-awareness-based family-planning Bridge is theoretically effective for postpartum women until they reestablish cycle regularity and can start using the Standard Days Method. CONCLUSION The Bridge can potentially be effective for postpartum women until they are eligible to use the Standard Days Method. Results from an efficacy study of the Bridge are described in a companion article.