LAUSR

OBJECTIVE To study the association among fertility treatments, treatment protocol, and offspring neoplasm risk up to the age of 18 years. DESIGN A population-based retrospective cohort. SETTING Soroka University Medical Center (SUMC), the single tertiary medical center and in vitro fertilization (IVF) unit in southern Israel. PATIENT(S) All offspring born at the SUMC between the years 1995 and 2018 after IVF treatment (the exposed group) and offspring conceived spontaneously (the unexposed group). INTERVENTION(S) The study was performed at the SUMC, the single tertiary medical center and IVF unit in southern Israel. The exposed and unexposed were matched with a ratio of 1:4, based on maternal age and calendar month of delivery. Data collection included a summary of the couple's medical records, delivery data, and offspring neoplasm diagnoses. MAIN OUTCOME MEASURE(S) Offspring neoplasm of any kind and time to diagnosis in each of the groups. RESULT(S) A total of 1,583 exposed and 5,874 offspring were included in the study. The incidences of offspring benign neoplasm were 14 (0.9%) versus 21 (0.4%), and the incidences of malignancies were 17 (1.1%) versus 29 (0.5%) among offspring of the IVF and spontaneous groups, respectively. The association between mode of conception and offspring neoplasm risk remained significant after adjusting for confounders, including mode of delivery and pregnancy complications such as hypertensive disorder, gestational diabetes mellitus, and preterm delivery compared with spontaneously conceived offspring. Among the IVF group, the increased risk for neoplasm was found among offspring who were transferred as fresh embryos, at an earlier stage of development (cleavage stage), or after three or more aspirated oocytes. CONCLUSION(S) IVF treatment is associated with offspring neoplasm risk; specifically, the risk was greater among offspring who were returned as fresh embryos, at an earlier embryotic stage (cleavage stage), or after three or more aspirated oocytes.