Trends and outcomes of fertility preservation in patients presenting with cancer during pregnancy or postpartum – A longitudinal observational cohort study

Hanna P. Nilsson^1*Riikka Bornhede^1,2Anna Johansson³Kenny A. Rodriguez-Wallberg^1,4*

• ¹Department of Oncology-Pathology, Karolinska Institutet, Solna, Sweden
• ²Department of Women’s Health, Division of Obstetrics, Karolinska University Hospital, Huddinge, Sweden
• ³Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
• ⁴Department of Reproductive Medicine, Division of Gynecology and Reproduction, Karolinska University Hospital, Stockholm, Sweden

OBJECTIVE: To assess the trends and outcomes of fertility preservation (FP) in women referred for FP-counselling and presenting with pregnancy associated cancer (PAC). METHOD: Prospective cohort study of all patients referred for FP-counseling between 2001 and 2024 to the FP-program of Karolinska University Hospital, Sweden. Baseline data, age, parity, disease stage, treatment characteristics and FP-methods were retrieved from clinical registries. RESULTS: 50 women with cancer diagnosed coincidentally with pregnancy (79%) or up to one year after delivery (21%) were referred for FP-counselling. Among them, 30 women choose to proceed with FP; 10 by either hormonal stimulation to freeze eggs/embryos or by ovarian tissue cryopreservation (OTC) after abortion/miscarriage, 10 by OTC at delivery, and 9 were planned for FP postpartum. The most common cancers were breast cancers (N=31, 62%), cervical cancer (N=6, 12%) and lymphoma (N=5, 10%). Most women diagnosed with cancer in the first trimester either terminated the pregnancy or had a miscarriage (76%). All patients diagnosed in the 2nd and 3rd trimester delivered through caesarian section (N=14), scheduled from week 31 and onwards. All patients diagnosed in the 3rd trimester started cancer treatment postpartum. In the FP-group, 57% cryopreserved ovarian tissue post-partum or post-abortion and 43% underwent ovarian stimulation for oocyte/embryo cryopreservation prior to chemotherapy initiation. Four women did FP after chemotherapy, three by ovarian tissue freezing and one through attempted, unsuccessful, hormonal stimulation. After a mean follow-up of 9.9 years, 45 patients were alive. The proportion of women having previous children at diagnosis was the same among the FP and noFP groups. At end of follow-up the percentage nulliparous women were 20% in the noFP group and 13% in the FP-group. CONCLUSIONS: Our observations underscore the need to ensure good multidisciplinary communication to inform patients presenting with PAC on the future risk for infertility and on the available FP-procedures. As FP have to be applied when the patients are not pregnant, these measures can be planned in connection with a cesarean-section, or after completion of cancer treatment. Current guidelines for FP lack specific recommendations for women with PAC, and specialized PAC guidelines also lack specific information on FP.