Finally good news for women who put off having children until age 35 or later. A recent study conducted by researchers at the University of Southern California in Los Angeles found that women who bear children after age 35 appear to significantly lower their risk of developing invasive ovarian cancer.

The population-based, case-controlled study examined the influence of hormone-related factors on the risk of developing invasive epithelial ovarian cancer by interviewing 477 women with ovarian cancer and 660 healthy women matched for age, race, and ethnicity.

Their “most striking” finding was the impact that age at last birth appeared to have on the risk of ovarian cancer. Compared with women who had never conceived, women who had their last child after age 35 have a 58 percent lower risk of developing ovarian cancer. If the birth of the last child was earlier, the reduction in risk of ovarian cancer was progressively less. For example, a last birth before age 25 was associated with only a 16 percent decrease in ovarian cancer risk.

The number of children a woman bears also influences her risk of developing the disease. Women who have four or more term pregnancies reduce their risk of developing ovarian cancer by 64 percent compared to women who have never conceived.

These findings were published in the July 2004 issue of the Journal of Fertility and Sterility.