New Study: Breastfeeding Really Does Reduce Your Risk of Ovarian Cancer

You know that breastfeeding has tons of benefits for your baby. That’s why the World Health Organization says you should only feed your baby breast milk for the first six months and then continue breastfeeding along with other foods for up to two years. Did you know that breastfeeding also has lots of benefits for your own health? You can read about all the benefits here.

One benefit mentioned for mothers is a decreased risk of breast and ovarian cancer, but the ovarian cancer benefit always had a lot of unanswered questions. The reduced risk was uncertain because not all studies found it. Some studies suggested that the benefit came from pregnancy not from breastfeeding. Studies were unable to show what type of ovarian cancers benefited, and how long a woman needed to breastfeed to get the benefit.

Now, the largest study on the link between breastfeeding and reduced ovarian cancer risk has answered all those questions. The study is published in the American Medical Association’s journal, JAMA Oncology.

The New Study

The study comes from a team of researchers at Harvard Medical School. They looked at the link between ovarian cancer and breastfeeding in about 15,000 women. The average age of the women was 57. This is what the study found:

  • Breastfeeding reduced the risk of all types of invasive ovarian cancers, including the most dangerous type, called high grade cancer.
  • The benefit was found whether a woman breastfed just one child or breastfed more babies.
  • Women who breastfed for just one to three months decreased their risk of ovarian cancer by 18 percent compared to women who never breastfed.
  • Women who breastfed for 12 months or longer decreased their risk of ovarian cancer by 34 percent compared to women who never breastfed.

Why This Study Is Important

This study confirms one more good reason to breastfeed, but there are already plenty of good reasons for that. This study is also important for ovarian cancer. This cancer is always near the top of the list for cancer deaths in woman. That’s because ovarian cancer may not cause symptoms until it is advanced. Advanced ovarian cancer is hard to treat. The survival rate at five years after diagnosis is less than 50 percent.

Risk reduction becomes even more important for cancers that are hard to treat. Up until now the only way for women to reduce their risk of ovarian cancer was to take birth control pills. This study adds another way to reduce the risk.

How Does Breastfeeding Reduce Cancer Risk?

Researchers don’t know exactly how breastfeeding reduces cancer risk. One possibility is that like birth control, breastfeeding stops the ovaries from ovulating. During ovulation, the lining of the outside of the ovaries, called the epithelium, goes through rapid cell turnover. It is during this turnover that cell mutations may occur, and some of these mutations can eventually lead to cancer. Epithelial cell cancer is the most common type of ovarian cancer.

Breastfeeding stops ovulation during an especially risky time. After pregnancy, your immune system is suppressed for a while and your body’s defense system is more likely to miss a gene mutation that might otherwise be removed. Breastfeeding’s effect on ovulation disappears after about six months, but the benefits of breastfeeding are long lasting. The researchers suspect that breastfeeding may also strengthen parts of your immune system that help fight cancer for a longer time.

Are You at Risk for Ovarian Cancer?

Ovarian cancer can occur during childbearing years, but it is most common between the ages of 50 and 60. Both ovarian cancer and breast cancer risk can be passed down through family genes. If you have a family history of breast or ovarian cancer, you could be at higher risk both. You should know the symptoms of ovarian cancer. Let your doctor know if you have any of these symptoms:

  • Bloating
  • Swelling of your belly
  • Weight loss
  • Belly pain or discomfort
  • Changes in bowel habits
  • Increased urinary frequency

Breastfeeding is the best way to feed your baby. There is no doubt about that. Knowing that you are also reducing your risk of ovarian cancer is an important added benefit, like icing on the cake.

Christopher Iliades
Dr. Chris Iliades is a medical doctor with 20 years of experience in clinical medicine and clinical research. Chris has been a full time medical writer and journalist since 2004. His byline appears in over 1,000 articles online including EverydayHealth, The Clinical Advisor, and Healthgrades. He has also written for print media including Cruising World Magazine, MD News, and The Johns Hopkins Children's Center Magazine. Chris lives with his wife and close to his three children and four grandchildren in the Boston area.

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