Short R V, Lewis P R, Renfree M B, Shaw G
Department of Anatomy, Monash University, Melbourne, Australia.
Lancet. 1991 Mar 23;337(8743):715-7. doi: 10.1016/0140-6736(91)90288-z.
We have recorded the duration of lactational anovulation and amenorrhoea in a well-nourished group of Australian women who breastfed their babies throughout the study. The data enabled us to compare the theoretical cumulative probability of conception among breastfeeding women who had unprotected intercourse irrespective of their menstrual status with that of those who had unprotected intercourse only during lactational amenorrhoea. Breastfeeding alone is not an effective form of contraception, since all the women in our study resumed normal ovulation while still breastfeeding. However, among women who have unprotected intercourse only during lactational amenorrhoea but adopt other contraceptive measures when they resume menstruation, only 1.7% would have become pregnant during the first 6 months of amenorrhoea, only 7% after 12 months, and only 13% after 24 months. Thus for our women it would be possible to extend the Bellagio Consensus Conference guidelines which stated that lactational amenorrhoea can only be relied on as a contraceptive for the first 6 months post-partum in women who are fully or almost fully breastfeeding. The lactational amenorrhoea method can be relied on for excellent contraceptive protection in the first 6 months of breastfeeding, irrespective of when supplements are introduced into the baby's diet; for women who continue to breastfeed the method can also give good protection for up to 12 months post partum. Once menstruation has returned, other forms of contraception are essential to prevent pregnancy.
我们记录了一组营养良好的澳大利亚女性的哺乳期无排卵和闭经持续时间，这些女性在整个研究过程中都进行母乳喂养。这些数据使我们能够比较无论月经状况如何都有过无保护性交的哺乳期女性与仅在哺乳期闭经期间有过无保护性交的女性受孕的理论累积概率。仅母乳喂养并非有效的避孕方式，因为我们研究中的所有女性在仍在哺乳时就恢复了正常排卵。然而，对于仅在哺乳期闭经期间有过无保护性交但在恢复月经时采取其他避孕措施的女性，在闭经的前6个月中只有1.7%会怀孕，12个月后为7%，24个月后为13%。因此，对于我们研究中的女性来说，可以扩展贝拉吉奥共识会议的指导方针，该方针指出，哺乳期闭经仅在产后6个月内可作为完全或几乎完全母乳喂养的女性的避孕方法。无论何时开始给婴儿添加辅食，哺乳期闭经法在母乳喂养的前6个月都可提供出色的避孕保护；对于继续母乳喂养的女性，该方法在产后长达12个月内也可提供良好的保护。一旦月经恢复，其他避孕方式对于预防怀孕至关重要。
