Characteristics and pregnancy outcomes of pregnant women by cancer diagnosis status.

11038 Background: Given the broad exclusion of pregnant patients from clinical trials, limited evidence exists on the impact of cancer diagnoses on pregnancy outcomes. This study aimed to describe patient characteristics and end of pregnancy events among women with and without a cancer diagnosis before pregnancy. Methods: This retrospective claims study used data from the Komodo Research Dataset between 01/01/2016–08/31/2023 to identify adult women with a known gestation of pregnancy record and end of pregnancy outcome. Eligible members needed to be continuously enrolled in medical and prescription drug plans for both 365 days before (baseline) and after the derived pregnancy start (index date). This pregnancy cohort was then stratified according to cancer status, evidenced by any cancer diagnosis during the baseline period, to allow assessment of pregnancy outcomes. Valid pregnancy outcomes included full or preterm live birth and pregnancy loss such as miscarriage, stillbirth, and elective termination. Only the earliest pregnancy observed for each eligible member was analyzed. Results: Among the 1,921,866 pregnant women included in the analyses, only 0.7% (N=12,723) of patients had any cancer diagnosis in the year prior to pregnancy start. Cancer patients were older than non-cancer patients (mean age: 33.8 and 29.2 years, respectively). Commercial medical insurance was more common (67.7% vs. 58.9%) among cancer vs. non-cancer patients and Medicaid enrollment was less common (30.3% vs. 40.6%) upon pregnancy start. The proportion of patients with a live birth was lower among cancer vs. non-cancer patients (59.7% vs. 67.1%), while the proportion with pregnancy loss was higher (31.6% vs. 25.8%). Medicaid enrollment was more common among patients that had a pregnancy loss relative to live birth for both cancer and non-cancer patients (35.5% vs. 27.5% and 45.7% vs. 38.7%, respectively). The proportion of black patients was higher among patients with a pregnancy loss relative to those with live birth in both cohorts (cancer: 11.1% vs. 8.3%; non-cancer: 16.9% vs. 13.7%), while the proportion of white patients was similar for cancer patients with a pregnancy loss vs. live birth (37.4% vs. 37.1%) and the proportion was lower for non-cancer patients (30.4% vs. 34.4%). Conclusions: Preliminary findings suggest pregnancy loss was more common among cancer patients than non-cancer patients. Regardless of cancer status, differences in insurance coverage and race were observed for patients with a live birth relative to patients with pregnancy loss. Additional research should be conducted to identify factors driving differences in pregnancy outcomes, such as in care management by race and ethnicity, particularly among the vulnerable population of cancer patients.