Women who had radiotherapy as a childhood cancer treatment face a significantly elevated risk of suffering a stillbirth or neonatal death, a new study found.

Researchers from Vanderbilt University reported that high doses of radiation to the pelvis when they were children raised the risk for women.

The increased risk is believed to be related to uterine damage caused by irradiation of the uterus and ovaries to treat childhood cancers including lymphoma, leukemia and Wilm's tumor.

In the study reported online in The Lancet, researchers analyzed nearly 5,000 pregnancies involving a parents who had radiotherapy and survived childhood cancer. Among these participants, 93 ended in stillbirth or neonatal death.

Of just 28 women who were given high doses of radiation, five resulted in stillbirths or early death.

High doses of radiation to the pelvis raised the risk for women, but not men. Men not affected because they produce new sperm throughout their lives. Chemotherapy drugs did not seem to harm future pregnancies.

The absolute risk of stillbirth or neonatal death was 3 percent overall. The link appeared only in those who received radiation treatment before puberty.

The team said doctors should take findings into account when caring for pregnant women with such medical histories."Careful management is warranted for pregnant women treated with high doses of pelvic irradiation before they have reached puberty," the researchers concluded.