RESUMO
BACKGROUND: There 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. OBJECTIVE: The study was conducted to evaluate forearm bone mineral density (BMD) of breastfeeding postpartum women using nonhormonal and progestin-only contraceptive methods. STUDY DESIGN: A 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. RESULTS: Baseline 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. CONCLUSIONS: Our findings suggest a preventive effect towards postpartum bone loss with progestin-only contraception in breastfeeding women.