THE INFLUENCE OF MEDROXYPROGESTERONE ON THE DURATION OF BREAST-FEEDING IN MOTHERS IN AN URBAN-COMMUNITY

Objective: To assess the effect of medroxyprogesterone acetate on lact ation when it is given immediately post partum. Design: Prospective co hort study with follow-up through 16 weeks post partum. Setting: Urban teaching hospital in Baltimore, Md. Participants: Consecutive sample (N=95) of mothers who were delivered of healthy, term newborns, had ho me telephones, received either medroxyprogesterone or non-hormonal con traception at discharge, and were currently breast-feeding their newbo rns. Main Outcome Measures: Lactation (duration and frequency) and tim ing of first introduction of formula were measured by weekly telephone interviews. Results: Maternal characteristics included the mean +/-SD maternal age (24+/-5 years), race (90% African American), history of pregnancy (63% multiparous), marital status or relationship (50% marri ed or living with partner), and medical assistance (81% of the recipie nts received aid). Women who were receiving medroxyprogesterone (n=43) were older (P<.05) and were more likely to be married (P<.05) compare d with those who were receiving nonhormonal contraception (n=52). No o ther factors that were likely to influence lactation were significantl y different. Groups did not differ in the baseline-planned duration of lactation. Follow-up data were obtained on 90 women (96%). The groups were comparable in the duration of lactation (medroxyprogesterone: 98 %, 74%, 55%, 47%, and 42% were breast-feeding at least once per day at 1, 4, 8, 12, and 16 weeks, respectively [median, 10.14 weeks],vs nonh ormonal contraception: 86%, 70%, 47%, 36%, and 30%, respectively [medi an, 6.57 weeks] [P=.19]). The percentage of subjects who were exclusiv ely breast-feeding at these times and the timing of formula introducti on also did not differ by group. Conclusion: Medroxyprogesterone, when given to mothers in an urban community immediately after delivery, ha s no detrimental effect on the duration of lactation, frequency of lac tation, and timing of introduction of formula within the first 16 week s post partum.