Fertility Regulation in Nursing Women IX. Contraceptive performance, duration of lactation, infant growth, and bleeding patternd during use of progesterone vaginal rings, progestin-only pills, norplant ® implant, and copper T 380-A intrauterine devices

This study evaluated the performance of progesterone vaginals rings (n = 187), progestin-only pills (n = 117) the Norplant® (n = 120), and Copper T 380-A intrauterine devices (n = 122) in lactating women. Contraceptive efficacy, bledding pattern, and influenced of the method upon breastfeeding duration and infant growth were compared with those of untreated women (n = 236) who relied on lactational infertility. Participants were healthy, 18 to 38 years, had a normal delivery, and were intending to breastfeed for as long as possible. Contraceptives were initiated as day 57 ± 3 pastpartum. Results are reported for the first year of use. All methods were highly effective, with pregnancy rates below 1%. None affected breastfeeding performance or the rate of infant growth. Users of the progestin-only methods experienced a period of lactational amenorrhea 4 to 5 months longer than did users of Copper T or untreated women. More than half of the women in each contraceptive group reported a bleeding in the first month after treatment initiation, which was not considered in the calculation of the duration of amenorrhea. Prolonged or frequent bleedings were infrequent. The proportion of bleedings lasting more than 10 days ranged from 0 in the progestin-only pills group to 7% in the Norplant implants group. The four methods, initiated around the eight postpartum week, provided effective contraception with no negative effects upon lactation or infant growth and without the bleeding problems associated with their use in nonlactating women.