Increased risk of congenital anomalies after fertility treatment is partially mediated by multiple birth: a population-based cohort study

The study investigates the extent to which multiple births mediate the association between fertility treatment and the risk of congenital anomalies. The findings indicate that while multiple births account for some of the increased risk, the majority of the excess risk of congenital anomalies associated with fertility treatment is independent of multiple births, suggesting that other factors related to infertility and treatment may also contribute significantly.