Effect of breast-feeding on postpartum menstruation, ovulation, and pregnancy in Alaskan Eskimos

Abstract

Use of life-table analysis for measurement of the conception rate among Alaskan Eskimos substantiates the findings previously reported that two factors serve to differentiate nursing from nonnursing women in relation to conception post partum. The first is the anovulatory period of postpartum amenorrhea which is found to be longer for nursing women than for nonnursing women. The second is that the number of anovulatory cycles after menstruation recurs is greater for nursing women than for nonnursing women. Both of these factors, being additive, result in a longer interval between pregnancies for nursing women than for nonnursing women where contraceptive methods are not used. The consistency of the findings for the Alaskan Eskimos with those reported for women in India show that the physiologic effect of nursing on the rate of conception is independent of climate.