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Contraception. 1997 Apr;55(4):225-32.

Contraceptives for lactating women: a comparative trial of a progesterone-releasing vaginal ring and the copper T 380A IUD.

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Center for Biomedical Research, The Population Council, New York, NY 10021, USA.


From approximately one week before normal ovulation resumes, lactating women require protection against pregnancy by a contraceptive that is safe for both infant and mother in a multicenter one-year study, the natural hormone, progesterone, delivered vaginally by a sequence of four contraceptive rings designed for continuous use, was evaluated as a contraceptive for nursing mothers in comparison with the Copper T 380A IUD. Individual rings release in effective average dose of 10 mg day for a 3 month period. Evaluation included measures of lactational performance as well as of contraceptive efficacy and safety to mother and child. Nine participating clinics enrolled 802 ring users and 734 IUD acceptors between postpartum days 29 and 63. Life table analyses were performed with parallel decrements for ring and IUD subjects. Continuation in the study and analysis required that subjects not stop breastfeeding. The ring, with a one-year pregnancy rate of 1.5 per 100, did not differ significantly from the IUD with respect to contraceptive effectiveness (p > 0.05). More than half of the ring subjects were continuing at 6 months post admission and a quarter (23.5 per hundred) were still using the ring and breastfeeding one year after admission. Women with the IUD, however, had higher continuation rates (p < 0.001) at both time points. The largest single decrement for each method was that for weaning. Ring users had more complaints of vaginal problems but had fewer vaginal disorders on examination. At 12 months postpartum, 46 per 100 continuing ring users remained in amenorrhea. Lactation performance and the health and weight gain of the infants were similar among users of either regimen.


A multicenter trial conducted in nine clinics in Asia, Latin America, North Africa, and the US indicated the progesterone-releasing vaginal ring (PVR) is a safe, effective contraceptive method for lactating women. Study participants, enrolled 4-9 weeks postpartum, agreed to fully or nearly fully breast feed for at least 3 months after admission. The ring released an average of 10 mg of progesterone per day for a 3-month period. The Copper T 380A IUD served as the non-hormonal control. A total of 431 and 533 woman-years of observation were accumulated in the PVR and IUD groups, respectively. After 12 months of use, the cumulative pregnancy rate was 1.5 per 100 in the PVR group and 0.5 per 100 in the IUD group. In the year following admission, 3.4% of PVR acceptors complained of heavy and/or prolonged bleeding. At 12 months postpartum, 46.2% of ring users compared with only one-sixth of IUD users remained amenorrheic. Although PVR acceptors reported more vaginal problems (e.g., discharge or leukorrhea), pelvic examinations were more likely to detect abnormalities in IUD users. The 6- and 12-month continuation rates were 52.5% and 23.5%, respectively, in the PVR group and 74.8% and 34.5%, respectively, in the IUD group. The predominant reason for discontinuation was weaning. Breast feeding performance and infant growth were within normal limits for the PVR and IUD. Both methods are highly effective and appropriate for use by lactating women from the second postpartum month forward; the PVR has the additional advantage of being user-controlled.

[Indexed for MEDLINE]

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