Female survivors of childhood cancer treated with abdominal radiotherapy who manage to conceive are at risk of delivering premature and low-birthweight offspring, but little is known about whether abdominal radiotherapy may also be associated with additional complications during pregnancy and labor. We investigated the risk of developing pregnancy and labor complications among female survivors of childhood cancer in the British Childhood Cancer Survivor Study (BCCSS).

Pregnancy and labor complications were identified by linking the BCCSS cohort (n = 17 980) to the Hospital Episode Statistics (HES) for England. Relative risks (RRs) of pregnancy and labor complications were calculated by site of radiotherapy treatment (none/abdominal/cranial/other) and other cancer-related factors using log-binomial regression. All statistical tests were two-sided.

A total of 2783 singleton pregnancies among 1712 female survivors of childhood cancer were identified in HES. Wilms tumor survivors treated with abdominal radiotherapy were at threefold risk of hypertension complicating pregnancy (relative risk = 3.29, 95% confidence interval [CI] = 2.29 to 4.71), while all survivors treated with abdominal radiotherapy were at risk of gestational diabetes mellitus (RR = 3.35, 95% CI = 1.41 to 7.93) and anemia complicating pregnancy (RR = 2.10, 95% CI = 1.27 to 3.46) compared with survivors treated without radiotherapy. Survivors treated without radiotherapy had similar risks of pregnancy and labor complications as the general population, except survivors were more likely to opt for an elective cesarean section (RR = 1.39, 95% CI = 1.16 to 1.70).

Treatment with abdominal radiotherapy increases the risk of developing hypertension complicating pregnancy in Wilms tumor survivors, and diabetes mellitus and anemia complicating pregnancy in all survivors. These patients may require extra vigilance during pregnancy.