Progestin-only contraception prevents bone loss in postpartum breastfeeding women

BackgroundThere are an increase in bone loss during the first 6 months postpartum and a complete recovery postweaning. A few studies of steroid contraceptive use during this period provide some evidence towards protection of bone loss with progestin-only contraceptive methods.ObjectiveThe study was conducted to evaluate forearm bone mineral density (BMD) of breastfeeding postpartum women using nonhormonal and progestin-only contraceptive methods.Study DesignA prospective cohort study of postpartum women had an analysis performed at 6 months postpartum correlating BMD with contraceptive use. Forearm BMD was measured 7–10 days, 3 months and 6 months postpartum. Eighty-two women were analyzed, comparing nonhormonal (54) and progestin-only (28) contraceptive methods. Information about breastfeeding duration, amenorrhea and body mass index was collected.ResultsBaseline characteristics of the study population showed no statistical differences between the groups. The median duration of breastfeeding for both groups was 183 days. A significant BMD decrease was observed for the nonhormonal group (p<.001); however, no statistical difference was detected for the progestin-only group. Body mass index, BMD at 7–10 days postpartum and total duration of breastfeeding were positively correlated with BMD at 6 months.ConclusionsOur findings suggest a preventive effect towards postpartum bone loss with progestin-only contraception in breastfeeding women.