For female cancer survivors who underwent radiation treatment as young girls, getting pregnant is only half the battle in raising a healthy family. Research found that these women are more prone to stillbirths or neonatal deaths, according to a report published Thursday online in Lancet.

Researchers, led by Dr. John Boice of the International Epidemiology Institute and Vanderbilt University, found that girls who received high-dose radiation treatment -- 2.5 Gy or more -- before reaching puberty were 12 times more likely to have stillborns or infants who died within 28 days of birth.

The scientists speculate that the high doses of radiation to the uterus impaired growth and blood flow, making conception possible, albeit difficult, but making it extremely hard to carry a fetus to term or to give birth to a healthy baby.
"The growth was likely impaired - and therefore difficult - when such women were able to become pregnant, for the fetus [having] to grow in a smaller uterus," Boice told DOTmed News.

The researchers do not have measurements on how underdeveloped the uteruses were.

In order to study the effects of high-dose radiation on birth, the researchers studied data from the Childhood Cancer Survivor Study, which included 25 U.S. institutions and one Canadian institution. All of the patients -- 1,148 men and 1,657 women -- were younger than 21 years at initial diagnosis of cancer and survived at least five years after diagnosis, according to the report.

Among the patients, there were 4,946 pregnancies.

From this study, the researchers concluded that the radiation did not have an effect on genetics, meaning men and women who were exposed to radiation to the testes or ovaries did not have an increased risk of stillbirth or neonatal deaths.

"The issue is related to damage to the uterus," explained Boice.

But women who experienced even low-dose radiation of 1 to 2.5 Gy weren't out of the woods. Four percent of women in that group experienced stillbirth or neonatal death.

When asked about what risks these pregnancies have on the mother, Boice explained that some cancer drugs could be harmful to the heart, and a pregnancy would put even greater stress on it.

This research, explained Boice, well help inform cancer survivors about the risks of becoming pregnant after having this type of radiation therapy at a young age. Women in this situation should consider seeing a specialist who deals with high-risk pregnancies, he said.

"Both the physician and cancer survivor can be aware of the possible adverse consequences," he said.

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