Risk of induced abortions in childhood cancer survivors

Background: The relative probability of pregnancy and parenthood in cancer survivors is reduced. Studies have shown that cancer survivors are concerned about the health of their offspring and the recurrence of their own cancer. This could lead to an increased risk of induced abortion. The aim of this study was to examine whether pregnancies of childhood cancer survivors (CCSs) who were 0 to 14 years old at diagnosis in 1971-2012 were more likely to result in induced abortions in comparison with population controls. Methods: Data from Finnish registries for cancer, births, and induced abortions were merged to identify 420 first pregnancies of CCSs and 2508 first pregnancies of age-matched population controls in 1987-2013. Poisson regression and logistic regression modeling were used to estimate incidence rates and relative risks (RRs) with 95% confidence intervals (CIs) of first pregnancies and induced abortions in CCSs in comparison with population controls. Results: The risk of first pregnancy was reduced in CCSs in comparison with population controls (RR, 0.72; 95% CI, 0.64-0.80), whereas the risk of a first pregnancy resulting in an induced abortion was similar in CCSs and population controls (RR, 1.01; 95% CI, 0.77-1.33). In subanalyses stratifying by decade of diagnosis and cancer treatment, the risk of induced abortion was similar in CCSs and population controls. Conclusions: Female CCSs do not have an overall increased risk of induced abortions. The reduced probability of pregnancy among CCSs highlights the continued need for interventions to preserve fertility at the time of a cancer diagnosis.