Pregnancy and cancer: A retrospective case series of obstetric, oncologic, and care-compliance outcomes.

e13549 Background: Two million women of reproductive age are diagnosed with cancer annually. Advances in cancer therapies have led to more women achieving pregnancy during or shortly after cancer diagnosis. These patients represent a clinically vulnerable population more likely to experience obstetrical and neonatal complications. We describe obstetric, oncologic, and care-compliance outcomes in patients with pregnancy-associated cancer and pregnancy occurring shortly after malignancy in a tertiary care medical center. Methods: We conducted a retrospective descriptive case series. Patients ≥ 18 years old with cancer who became pregnant January 2020-January 2025 were identified through ICD-10 codes. Patients were included if diagnosed with cancer during pregnancy or if pregnancy occurred within five years of cancer diagnosis without documented long-term remission. Those in remission beyond five years were excluded. Electronic medical records were reviewed for demographics, gynecologic history, malignancy history, and pregnancy outcomes. Compliance, defined as attending two and six-week postpartum obstetric visits and oncology appointments up to six months postpartum, was recorded. Descriptive statistics were used. Results: The cohort (n = 20) was majority black non-Hispanic (45%) with public insurance (50%). Average age at cancer diagnosis was 30.8 years (SD = 7.5) and 33.6 years (SD = 5.1) at pregnancy. Breast cancer (25%) was the most represented cancer type followed by sarcoma (15%), lymphoma (15%), cervical cancer (15%). Remaining cases included melanoma, astrocytoma, ovarian cancer, leukemia, and cholangiocarcinoma (each 5%). Pregnancy outcomes included spontaneous vaginal delivery (40%), cesarean delivery (30%), spontaneous abortion (15%), and termination (15%). Among live births, 57% were preterm ( < 37 weeks). Maternal complications included pre-eclampsia (36%) and preterm premature rupture of membranes (14%). Non-attendance occurred in 46% of patients for obstetric follow-up and 30% for oncology follow-up. Four patients (20%) experienced cancer progression during pregnancy or within six months postpartum. These patients were more likely to have ongoing disease activity one year after diagnosis. No clear associations were observed between visit compliance and short-term survival outcomes. Conclusions: This study highlights the complexity of pregnancy in patients with active or recent malignancy in a predominantly minority population. High rates of obstetric complications and preterm birth were observed. Compliance with peripartum obstetric and oncologic care was suboptimal, reflecting the vulnerability of this population. Limitations include small sample size and incomplete external records. Larger, multi-center studies are needed to better define maternal, neonatal, and oncologic outcomes and to develop interventions to improve care.