Cancer during pregnancy and child health perspectives: Evidence from real-world data.

11013 Background: Pregnancy-associated cancer (PAC), is rare but increasingly encountered, likely reflecting delayed childbearing and the rising incidence of early-onset cancers. However, real-world evidence on short- and long-term offspring outcomes following PAC remains limited, particularly with respect to childhood chronic and inflammatory conditions. Methods: We conducted a retrospective cohort study using electronic medical records from Clalit Health Services, Israel’s largest integrated healthcare system. Pregnancies among women aged 18–50 years between 2000 and 2024 were identified including PAC and non-PAC (controls). Annual incidence rates were calculated overall and by maternal age group. Short-term maternal, pregnancy, and neonatal outcomes were compared between PAC-exposed and cancer-free pregnancies using multivariable regression models. To assess long-term child outcomes, we included all identified PAC cases and their offspring and extended follow-up to capture chronic conditions (as documented diagnosis within electronic medical records) that typically manifest later in childhood. Results: The cohort included 3,561 PAC and 28,361 non-PAC participants. PAC incidence increased substantially over time, with highest incidence observed among women aged 35–45 years. Breast cancer was the most frequently diagnosed invasive malignancy during pregnancy. Gestational age at delivery was comparable between PAC and non-PAC pregnancies, although PAC-exposed offspring were slightly more likely to be born with low birth weight (HR 1.03; 95% CI 1.01–1.05; P = 0.01).In follow-up analyses, heterogeneous and outcome-specific differences in child health were observed. PAC exposure was associated with higher risks of inflammatory and immune-related conditions, including inflammatory bowel disease (HR 1.16; 95% CI 1.03–1.32; P = 0.013) and allergic conditions (HR 1.20; 95% CI 1.03–1.39; P = 0.017). Associations with asthma (HR 1.12; 95% CI 1.00–1.26; P = 0.056) and cardiovascular conditions (HR 1.16; 95% CI 1.00–1.26; P = 0.057) were also observed yet reached borderline statistical significance. All models were adjusted for maternal BMI, hypertension, diabetes, cardiovascular disease, age at delivery, socioeconomic status, depression, and child sex. Conclusions: The incidence of PAC has increased markedly over the past decade. Our findings suggest that cancer during pregnancy may be associated with increased risk of inflammatory/immune-related conditions in the born children. Ongoing analyses and preclinical models will further clarify the long-term clinical significance of these findings and their implications for maternal–child survivorship care.