Breastfeeding patterns and return to fertility in Australian women.

Abstract

The purpose of this study was to understand the relationship between infant feeding patterns and the return of fertility during lactation. Mother-infant pairs were followed up prospectively from the first week postpartum until the return of two normal menstrual bleeds (as judged by the woman) or pregnancy This study was conducted in the Sydney and Melbourne areas of Australia, and was part of a seven-country research project. Six hundred and twenty-four Australian mother-infant pairs participated in the study Follow-up interviews occurred in the mothers' homes every two weeks. Mothers completed a daily diary record chart of vaginal bleeding and infant feeding, and completed a detailed diary card of the time and duration of breastfeeds and the frequency and nature of all other feedings once every two weeks. MAIN OUTCOME MEASURES The main outcomes of the study were measured as the median duration of lactational amenorrhoea and lifetable pregnancy rate during lactational amenorrhoea. The median duration of amenorrhoea in the Australian breastfeeding women who participated in the study was over 8.5 months. Breastfeeding was shown to be an effective method of fertility control in that no non-contracepting, sexually active, amenorrhoeic, breastfeeding woman became pregnant in the first six months after delivery. Regular supplements commenced on average at five months and the Australian women rarely introduced noncaloric (water), caloric (juices), or milk-based supplements before this time. This confirmed the Bellagio Consensus and the effectiveness of the Lactational Amenorrhoea Method.