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Effects of Breastfeeding on Breast Cancer

Research Synthesis Paper: Induced Abortion and Breast Cancer

Breast cancer risk is reduced in proportion to the length of time a mother breastfeeds. Women who exclusively breastfeed their infants will also cease their regular menstrual cycles for up to two years, which will reduce their risk of breast cancer. Many of the cycles a woman initially regains while breastfeeding are anovulatory (do not produce an egg). These cycles are lower in estrogen and do not increase the mother’s risk of breast cancer as much as normal ovulatory cycles do. By contrast, a woman who lactates for the first time over 10 years after an induced abortion has a significantly increased risk of breast cancer.1)

1) Janet R. Daling, Kathleen E. Malone, Lynda F. Voigt, Emily White, and Noel S. Weiss, “Risk of Breast Cancer among Young Women: Relationship to Induced Abortions,” Journal of the National Cancer Institute 86 (1994): 1584-1592.