You probably already know that breastfeeding will give your baby a healthy start. But that’s not its only health benefit. It can also lower your  breast cancer risk. 

“Breastfeeding is more than a wonderful bonding opportunity; it also lowers your risk for some types of cancer,” says Therese Bevers, M.D., medical director of MD Anderson’s Lyda Hill Cancer Prevention Center. 

Why? Read on as Bevers explains the science behind this health benefit and wellness dietitian Lindsey Wohlford provides tips on where to find breastfeeding support. 

How does breastfeeding reduce your breast cancer risk?

Most women who breastfeed experience hormonal changes during lactation that delay the return of their menstrual periods after childbirth. This reduces their lifetime exposure to hormones like estrogen, which can promote breast cancer cell growth. 

The body also sheds breast tissue naturally during pregnancy and breastfeeding. “And, in that process,” Bevers explains, “it is possible you’ll shed some cells that had the potential to become abnormal.” 

Does breastfeeding prevent any other types of cancer?

Yes. “Breastfeeding can also help lower your ovarian cancer risk by preventing ovulation,” says Bevers. “The fewer times you ovulate, the less exposure you’ll have to estrogen and abnormal cells that could one day become cancer.” 

How long do you have to breastfeed to reap the benefits?

You should breastfeed exclusively for at least six months to get the health benefits, according to the American Institute for Cancer Research and the World Health Organization. That means your baby receives only breast milk — no solids, water or other liquids.   

After that, you can gradually begin introducing foods like finely ground cereals, puréed fruits and vegetables. But breast milk should continue to provide at least half of your child’s nutritional needs. 

“Breastfeeding for longer than six months benefits your child’s health and yours,” says Bevers. “The longer you breastfeed, the more protection you’ll receive.”  

In a study by the Collaborative Group on Hormonal Factors in Breast Cancer, researchers found that for every 12 months a woman breastfed, her risk of breast cancer decreased by 4.3%. The study compared mothers who breastfed to those who didn’t. It also found that the 12-month time period could be with either one child or several children over time.   

Australian researchers found that women who breastfed for more than 13 months were 63% less likely to develop ovarian cancer than women who breastfed for less than seven months. Women who breastfed multiple children for more than 31 months could reduce their ovarian cancer risk by up to 91%, compared to women who breastfed for less than 10 months.