EFFECTIVENESS OF LACTATIONAL AMENORRHEA IN PREVENTION OF PREGNANCY INMANILA, THE PHILIPPINES - NONCOMPARATIVE PROSPECTIVE TRIAL

Objective-To determine the contraceptive efficacy of the lactational a menorrhoea method. Design-Non-comparative prospective trial. Setting-U rban Manila, the Philippines. Subjects-485 lower income, educated wome n with extensive experience of breast feeding. Intervention-Women were offered all available contraceptives for use after birth. Those who c hose the lactational amenorrhoea method were taught the method, screen ed for the study, and followed for 12 months to determine the risk of pregnancy when the method was used. Main outcome measures-Life table p regnancy rates during correct and incorrect use of the method, censore d monthly in the event of sexual abstinence or the use of another cont raceptive method. Results-The lactational amenorrhoea method was 99% e ffective when used correctly (that is, during lactational amenorrhoea and full or nearly full breast feeding for up to six months). At 12 mo nths the effectiveness during amenorrhoea dropped to 97%. Conclusions- The lactational amenorrhoea method provided as much protection from pr egnancy as non-breast feeding women experience with non-medicated intr auterine devices and barrier methods. The contraceptive effect of lact ation cannot be attributed to lactational or postpartum abstinence.