Pregnancy and labour complications in female survivors of childhood cancer: the British childhood cancer survivor study

Background: 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 labour. We investigated the risk of developing pregnancy and labour complications among female survivors of childhood cancer in the British Childhood Cancer Survivor Study (BCCSS).

Methods: Pregnancy and labour 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 labour 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.

Results: A total of 2,783 singleton pregnancies among 1,712 female survivors of childhood cancer were identified in HES. Wilms tumour survivors treated with abdominal radiotherapy were at 3-fold risk of hypertension complicating pregnancy (RR=3.29, 95%CI=2.29-4.71), whilst all survivors treated with abdominal radiotherapy were at risk of gestational diabetes mellitus (RR=3.35, 95%CI=1.41-7.93) and anaemia complicating pregnancy (RR=2.10, 95%CI=1.27-3.46) compared to survivors treated without radiotherapy. Survivors treated without radiotherapy had similar risks of pregnancy and labour complications as the general population, except survivors were more likely to opt for an elective Caesarean section (RR=1.39, 95%CI=1.16-1.70).

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