A new study is drawing a potential link between child birth and breast cancer.
Researchers say a woman's risk of breast cancer goes up in the five years or so after she has a child.
One third of the 25,000 cases diagnosed in women under 45 are incidents of postpartum breast cancer.
"Women are putting off first time pregnancy til later in life and I think that may have something to do with it," says Dr. Lisa McGrail, an oncologist with the Medical Faculty Associates at George Washington University.
There's also the possibility, doctors say, that more women are diagnosed sooner because they were pregnant. Inflammation of the breast and hormones are also big factors.
"Some speculate it may be the hormonal surges during pregnancy that may stimulate the growth of some pre-existing abnormal cells in the breast," McGrail says.
Sarangi Bhatia tells ABC7's Natasha Barrett that she was diagnosed with breast cancer at the age of 32, when her son was three years old.
Bhatia is doing well now.
Doctors say they don't want these findings about postpartum breast cancer to scare young mothers. Most cancers in women are still diagnosed when women are in their 60s.
And there is still more research to be done.