The findings of new research suggest breastfeeding a baby, even for a short period of time, may reduce a woman’s risk of getting ovarian cancer.
While breast feeding for longer periods of time reduced a woman’s risk of ovarian cancer by up to 34%, even three months or less of breastfeeding reduced the risk by about 18%, according to findings published this month in the medical journal JAMA Oncology.
Researchers from Harvard Medical School analyzed data on nearly 10,000 women with ovarian cancer, and compared them to 14,000 control subjects participating in the Ovarian Cancer Association Consortium from November 1989 to December 2009.
The study involved questionnaires and interviews to collect data on the women’s breastfeeding history, including duration per child breastfed, age at first and last breastfeeding, and years since last breastfeeding.
According to the findings, breastfeeding was associated with a 24% reduced risk of invasive epithelial ovarian cancer. Longer breastfeeding duration and shorter time since the last breastfeeding episode were linked with a further decrease in risk.
The researchers determined that breastfeeding for one to three months was associated with an 18% decreased breast cancer risk, while breastfeeding for 12 or more months was linked to a 34% lower risk.
Having breastfed more recently was associated with a reduction in risk that lasted for decades. However, researchers determined having breastfed at all led to a benefit lasting for at least 30 days.
Compared to women who never breastfed, breastfeeding was linked to a 44% reduced risk of ovarian cancer. Having breastfed at all in the last 30 years decreased a woman’s risk by 17%.
More than 200,000 women in the United States are diagnosed with ovarian cancer every year, according to the American Cancer Society. Women who are diagnosed often have a poor prognosis. About 45% of women diagnosed with ovarian cancer survive at least five years after diagnosis.
While the relationship between breastfeeding and ovarian cancer is unclear, and the study does not prove a causal link, it does indicate an association between breastfeeding and a reduced risk of ovarian cancer, the researchers determined.
“This large study with extensive information on breastfeeding provides epidemiological evidence that breastfeeding, a potentially modifiable factor, may confer significant reduction in ovarian cancer risk, including high-grade serous, the deadliest subtype,” the researchers wrote.