The World Health Organization multinational study of breast-feeding and lactational amenorrhea. III. Pregnancy during breast-feeding. World Health Organization Task Force on Methods for the Natural Regulation of Fertility.
OBJECTIVE
To determine the risk of pregnancy during lactational amenorrhea relative to infant feeding status.


METHODS
Prospective longitudinal study.


METHODS
Five developing and two developed countries.


METHODS
Four thousand one hundred eighteen breast-feeding mother-infant pairs.


METHODS
Infant feeding practices, menstrual status, and pregnancy were measured.


METHODS
Life-table rates of pregnancy.


RESULTS
In the first 6 months after childbirth, cumulative pregnancy rates during amenorrhea, depending on how the end of amenorrhea was defined, ranged from 0.9% (95% confidence interval [CI] = 0%-2%) to 1.2% (95% CI = 0%-2.4%) during full breast-feeding, and from 0.7% (95% CI = 0.1%-1.3%) to 0.8% (95% CI = 0.2%-1.4%) up to the end of partial breast-feeding. At 12 months, the rates ranged from 6.6% (95% CI = 1.9%-11.2%) to 7.4% (95% CI = 2.5%-12.3%) during full breast-feeding, and from 3.7% (95% CI = 1.9%-5.5%) to 5.2% (95% CI = 3.1%-7.4%) up to the end of partial breast-feeding.


CONCLUSIONS
These results support the Bellagio Consensus on the use of lactational amenorrhea for family planning, and confirm that the lactational amenorrhea method is a viable approach to postpartum contraception.
D000328:Adult; D000568:Amenorrhea; D001942:Breast Feeding; D003075:Coitus; D003267:Contraception; D003906:Developing Countries; D005260:Female; D006801:Humans; D007774:Lactation; D008598:Menstruation; D011247:Pregnancy; D011446:Prospective Studies; D013997:Time Factors; D014944:World Health Organization