er unprotected intercourse reduces risk of pregnancy by at least 75%9 Lactational Amenorrhea Method: LAM is a highly effective, temporary method of contraceptioni0 Source: Trussell J, Stewart F, Contraceptive Efficacy. In Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Kowal D, Guest F, Contraceptive Te