NEW YORK - Pregnant women who survived childhood cancers, primarily those treated with radiation to the pelvic area, are more likely to deliver early, according to data from the Childhood Cancer Survivor Study.

In the Journal of the National Cancer Institute, Dr. Lisa B. Signorello, from the International Epidemiology Institute in Rockville, Maryland, and associates report their analysis of 1,264 female childhood cancer survivors reporting 2201 single-infant live births. These women were compared with a "control" group of 601 of their sisters without cancer reporting 1175 single-infant live births.

Childhood cancer survivors' children were nearly twice as likely to have been delivered earlier than 37 weeks than children in the control group.

In general, survivors' children were also more likely to have been born at less than about 5.3 pounds, but this difference was not statistically significant after of other contributing factors. Similarly, these infants were no more likely to be born preterm or before complete maturation.

Radiation therapy near the uterus had a significant impact on birth outcomes. Compared with survivors who were not treated with radiation, the risk rose according to dosage among the women who underwent radiation. Infants born to mothers treated with more than 500 cGy to the uterus were also more likely to be born small for gestational age and to have a low birth weight.

In contrast, the investigators observed no significant associations between preterm birth and radiation exposure to the ovaries or pituitary gland. Chemotherapy also appeared to have little effect on preterm birth, low birthweight, and small for gestational age births.

In a related editorial, Dr. Leslie R. Schover, at the University of Texas M. D. Anderson Cancer Center in Houston, comments that the research by Signorello's group fails to analyze other pregnancy complications caused by cancer treatment, such as an increased rate of miscarriage and medical terminations.

"Given the complex terrain our young survivors need to traverse (with regard to fertility), we should design patient and professional educational materials that map out the paths to making informed decisions," Schover concludes.