1Ramos R, Kennedy KI, Visness CM. Effectiveness of lactational amenorrhea in prevention of pregnancy in Manila, The Philippines: non-comparative prospective trial. Br Med J 1996; 313: 909–12.
Key Results
The lactational amenorrhoea method was 99% effective when used correctly (that is, during lactational amenorrhoea and full or nearly full breast feeding for up to six months). At 12 months the effectiveness during amenorrhoea dropped to 97%.
Conclusion
The lactational amenorrhoea method provided as much protection from pregnancy as non-breast feeding women experience with non-medicated intrauterine devices and barrier methods. The contraceptive effect of lactation cannot be attributed to lactational or postpartum abstinence.