THE WORLD-HEALTH-ORGANIZATION MULTINATIONAL STUDY OF BREAST-FEEDING AND LACTATIONAL AMENORRHEA - II - FACTORS ASSOCIATED WITH THE LENGTH OFAMENORRHEA

Objective: To determine the relation between infant feeding practices (and other factors) and the duration of postpartum amenorrhea, and to establish whether there are real differences in the duration of postpa rtum amenorrhea for similar breast-feeding practices in different popu lations. Design: Prospective, nonexperimental, longitudinal follow-up study. Setting: Five developing and two developed countries. Patient(s ): Four thousand one hundred eighteen breast-feeding mothers and their infants. Intervention(s): Breast-feeding women collected ongoing info rmation about infant feeding and family planning practices, plus the r eturn of menses. Fortnightly follow-up occurred in the women's homes. Main Outcome Measure(s): A multivariate analysis explored the associat ion between the risk of menses return and 16 infant feeding variables and 11 other characteristics. Result(s): Ten factors (in addition to c enter effects) were significantly related to the duration of amenorrhe a. Seven of these were infant feeding characteristics and the remainin g three were high parity, low body mass index, and a higher frequency of infant illness. Conclusion(s): The breast-feeding stimulus is stron gly linked to the duration of postpartum amenorrhea. Cross-cultural ef fects also are extremely important and may have caused the variations in feeding, the variation in amenorrhea, or both. (Fertil Steril(R) 19 98;70:461-71. (C)1998 by American Society for Reproductive Medicine.).