According to the American Cancer Society, “Women who have been pregnant and carried it to term have a lower risk of ovarian cancer than women who have not. The risk goes down with each full-term pregnancy. Breastfeeding may lower the risk even further.” The protective effect of pregnancy can last twelve years or more. The spacing of births does not appear to be a factor.
“If she’s under 30, add a decreased risk of breast cancer.”
Although women’s heath groups agree that giving birth at a young age decreases a woman’s lifetime risk of breast cancer, the exact maternal age limit is hard to pinpoint. BreastCancer.org states “Women who have never had a full-term pregnancy, or had their first full-term pregnancy after age 30, have an increased risk of breast cancer,” while the Susan G. Komen Foundation reports that childbirth protects first-time mothers as old as 35. The underlying hormonal mechanisms are not fully understood; see this Science Daily piece for a recent study on mice that may provide some answers.
“And preliminary research suggests that some of the baby’s stem cells will stay behind to repair her injuries for years or even decades after the child’s birth.”
Much research remains to be done concerning this phenomenon, which is known as fetomaternal microchimerism. “Fetal cells exhibit a remarkable ability to migrate across the placenta into the mother and to integrate with diverse maternal tissues and organs, apparently homing in particularly to sites of damage and disease.” Recent studies of mother mice who suffered from strokes and heart failure indicate that fetal cells have a healing effect.
P.S.– Many thanks to SPL supporters Natalie and Andrew V. for allowing their son Bennie to model for the picture.