2025-07-04 カロリンスカ研究所(KI)
<関連情報>
- https://news.ki.se/planned-c-sections-increase-the-risk-of-certain-childhood-cancers
- https://onlinelibrary.wiley.com/doi/10.1002/ijc.70027
小児期の分娩様式とリンパ芽球性白血病のリスク-スウェーデンの集団ベースのコホート研究 Mode of delivery and the risk of lymphoblastic leukemia during childhood—A Swedish population-based cohort study
Christina-Evmorfia Kampitsi, Hanna Mogensen, Mats Heyman, Maria Feychting, Giorgio Tettamanti
International Journal of Cancer Published: 04 July 2025
DOI:https://doi.org/10.1002/ijc.70027
Abstract
Cesarean section (CS) rates have been increasing beyond medically warranted thresholds, despite potential long-term adverse outcomes. Previous research on CS delivery and childhood leukemia is conflicting but suggests an increased acute lymphoblastic leukemia (ALL) risk in children delivered by planned CS. It has been suggested that maternal and pregnancy conditions predisposing to pregnancy complications might confound such an association; therefore, we aimed to elucidate the relationship between delivery mode and ALL in Swedish children. To this end, we studied all children born in Sweden between 1982–1989 and 1999–2014, when comprehensive information on delivery mode was available (n = 2,442,330). Pregnancy conditions, delivery mode, and childhood ALL diagnoses (<20 years) were retrieved from nationwide registers. Cox proportional hazards regression was used to assess the association between delivery mode and childhood ALL, adjusting for maternal and pregnancy conditions. We observed an increased ALL risk among children delivered by planned CS (HR = 1.21, 95% CI 0.96–1.54), driven by B-cell precursor ALL (HR = 1.29, 95% CI 1.01–1.67). The associations were concentrated among boys and at peak ages of ALL incidence (≤5 years) and persisted after accounting for potential confounders, including maternal and perinatal factors. Unplanned CS was not associated with increased risk of childhood ALL. Our nationwide study supports an association between planned CS and an increased B-cell precursor ALL risk in Swedish children, irrespective of maternal and pregnancy conditions. Possible underlying mechanisms, such as lack of exposure to maternal vaginal microbiota or decreased stress hormones at birth, require further exploration.
What’s New?
Infants born by cesarean section (CS) are at increased risk of certain long-term adverse health outcomes, including childhood leukemia. The influence of maternal factors, pregnancy, and perinatal conditions on these associations, however, remains unclear. In this study of more than 2 million children born in Sweden, the authors examined relationships between delivery mode and risk of childhood acute lymphoblastic leukemia (ALL). Analysis of data from nationwide registers reveals that planned, but not unplanned, CS is associated with an increased risk of childhood ALL, independent of maternal and perinatal factors. Further investigation is needed to elucidate biological mechanisms underlying this association.
