Fertility treatments among female cancer survivors giving birth - a Finnish register-based study.

BACKGROUND: Long-term survival rates for most types of childhood cancers have improved dramatically over the past decades. However, because of advances in multimodality treatments, cancer survivors nowadays more often face long-term complications, including diminished gonadal and reproductive function. The aim of this study was to identify whether the use of fertility treatments among early onset (0-34 years) cancer survivors giving birth differed from that among siblings giving birth and to identify the subgroups of cancer survivors that were most likely to require fertility treatments.

MATERIAL AND METHODS: Nationwide cancer and birth registries were merged to identify 1974 post-diagnosis deliveries of cancer survivors and 6107 deliveries of female siblings in 2004-2013. Unconditional multivariate logistic regression models were used to estimate the risk for different fertility treatments namely assisted reproductive technology, intrauterine insemination and ovulation induction. We adjusted for maternal age, year of delivery, parity and smoking.

RESULTS: We found overall significantly increased odds for use of any fertility treatments in survivors compared to siblings (OR 1.84, 95% CI 1.18-2.86). As time from cancer treatment increased, the odds for need of fertility treatments increased, being highest at 11 to 15 years post cancer treatment (OR 2.88, 95% CI 1.13-7.30). Survivors diagnosed at ages 25-34 years had the highest odds for use of fertility treatments compared to siblings (OR 2.31, 95% CI 1.01-5.32).

CONCLUSIONS: Our study supports previous findings indicating that cancer survivors have an increased risk for subfertility. Survivors diagnosed in their childhood had the lowest risk for fertility treatment and seemed to get pregnant with less extensive fertility treatments than survivors diagnosed as adults. Time elapsed from cancer treatment played a central role, increasing the need for fertility treatments compared to siblings, suggesting that cancer therapies might lead to diminished ovarian reserve.