This report describes the pregnancy outcomes among 7 survivors of childhood Wilms tumor, who were treated on one of the National Wilms Tumor Studies (NWTS) with radiation therapy (RT) portals that extended beyond the flank.

Pregnancy outcomes among female survivors of childhood Wilms tumor treated with abdominal irradiation in NWTS 1-4 were analyzed as part of the long-term follow-up study. Medical records and maternal questionnaires were used to gather information on pregnancy outcomes.

A total of 130 patients received abdominal RT and survived to at least 15 years of age. Seven patients (5.4%) had at least 1 recorded pregnancy. The extent of RT fields was ascertained in 126 patients. For 4 patients, the extent of RT fields could not be determined. Twelve girls received RT using portals that included the upper abdomen but not the entire pelvis. Ten pregnancies were recorded in 5 of these patients; 9 resulted in live births, and 1 resulted in a miscarriage. One hundred fourteen girls received RT using portals that included the entire abdomen and pelvis. The abdominal RT dose distribution among these 114 patients was as follows: 9 received 0-10.49 Gy, 22 patients received 10.5-14.99 Gy, and 83 patients received 15+ Gy. Four pregnancies were recorded in 2 of these patients. After 21 Gy to the abdomen and pelvis in 1 patient, all 3 pregnancies resulted in miscarriages and fetal deaths. However, after 10.5 Gy, a normal live birth was reported in the other patient. Pregnancy-related complications were also more common if the RT portals included the pelvis.

Fertility can be preserved in children with Wilms tumor after upper abdominal RT (10-20 Gy) that does not include the entire pelvis. In rare instances, fertility can be preserved after low-dose whole-abdominal RT (10.5 Gy). The indications and dosages for RT currently used have been greatly refined compared to NWTS-1 and NWTS-2. Childhood Wilms tumor survivors should be considered to be at a high risk for infertility and pregnancy-related complications during their reproductive years. Prompt obstetric evaluation is indicated for optimal prenatal, antenatal, and postnatal care.