Impact of Cancer on Pregnancy and Fertility Service Use in Reproductive-Aged Women

INTRODUCTION: Advances in oncologic therapy have extended survival among women of reproductive age, repositioning fertility and family-building as core survivorship concerns. Population-level data on post-diagnosis pregnancy and real-world fertility-care utilization across cancers remain limited. This study evaluated post-diagnosis pregnancy and fertility-care utilization among reproductive-aged women (18-45 years) with incident invasive cancer and examined variation by age, parity, race, and neighborhood social vulnerability. METHODS: We conducted a retrospective cohort study using 2 large U.S. datasets. The primary cohort was drawn from IBM MarketScan (2013-2018). A validation cohort was assembled using Epic Cosmos (2018-2021), an electronic health record-based patient registry. Women aged 18 to 45 years with incident invasive cancer were matched to cancer-free controls. The main exposure was incident cancer diagnosis. The primary outcome was subsequent pregnancy after diagnosis, with secondary outcomes including fertility evaluation, fertility testing, and fertility preservation. Hazard ratios (HRs) and 95% confidence intervals (CIs) measured associations, including subgroup analyses by parity, age, race, and social vulnerability. RESULTS: In the MarketScan cohort, pregnancy occurred in 103 (2.3%) survivors versus 388 (4.5%) controls (HR = 0.47, 95% CI = 0.38-0.59). Survivors had higher rates of fertility evaluation (42 [0.9%] vs 25 [0.3%]; HR = 3.00, 95% CI = 1.81-4.97), fertility testing (1759 [39.7%] vs 1031 [11.9%]; HR = 4.23, 95% CI = 3.91-4.58), and fertility preservation (34 [0.8%] vs 25 [0.3%]; HR = 2.36, 95% CI = 1.39-4.00), although absolute preservation rates remained low. Associations were strongest among nulliparous women (pregnancy HR = 0.50, 95% CI = 0.37-0.69). Increasing age reduced pregnancy (HR = 0.75, 95% CI = 0.73-0.78) and preservation (HR = 0.86, 95% CI = 0.80-0.92). No racial or neighborhood social vulnerability trends were identified. Results were replicated in the Cosmos validation cohort, with consistently higher fertility evaluation (HR = 7.47), testing (HR = 5.54), and preservation (HR = 6.56) after cancer diagnosis. CONCLUSIONS: Among reproductive-aged women, cancer diagnosis was associated with fewer and delayed pregnancies and persistently low absolute uptake of fertility-preserving care, particularly among nulliparous and older patients. These findings highlight the need for early, standardized onco-fertility counseling, automatic pre-treatment referral for patients undergoing gonadotoxic therapy, and policies designed to mitigate barriers to fertility care.