P-769 fertility treatments and the risk for long-term respiratory morbidity of the offspring; a sibling analysis

Abstract Study question Is the risk of long-term respiratory morbidity increased among children born following fertility treatments (in-vitro fertilization and ovulation induction)? Sibling analysis to maximize confounder control. Summary answer Fertility treatments do not appear to be an independent risk factor for long-term respiratory morbidity of the offspring up to 18 years of age. What is known already Studies have found an association between fertility treatments and long-term respiratory morbidity of the offspring, specifically obstructive sleep apnea (OSA). Study design, size, duration A retrospective population-based cohort analysis was performed, including all sibling deliveries occurring between 1991 and 2021 at a tertiary medical center. Offspring were followed-up until the age of 18 years. Participants/materials, setting, methods The study population included 10,691 siblings of women who had at least one spontaneous pregnancy and at least one pregnancy following fertility treatments. A Kaplan–Meier survival curve was used to compare the cumulative respiratory morbidity incidence, and a multivariable Cox survival hazards regression model was used to control for confounders. Main results and the role of chance There were 5,869 siblings (54.9%) conceived following fertility treatment and 4,822 spontaneously conceived siblings (45.1%). Using a univariable analysis, respiratory morbidity was higher among siblings born following fertility treatments as compared with those conceived spontaneously (9.6% vs. 8.4%; p = 0.023), in particular, OSA (2.6% vs. 1.8%; p = 0.005). However, using a Kaplan-Meier survival curve, being born following fertility treatments did not have a higher cumulative incidence rate of long-term respiratory morbidity (Log-Rank, p = 0.339). Likewise, when using a Cox regression model, controlling for confounders such as maternal age, diabetes mellitus, preterm delivery, and hypertensive disorders, the association between being born following fertility treatments was no longer associated with long-term respiratory morbidity (adjusted HR = 1.0, 95% CI 0.88-1.14, p = 0.957). Limitations, reasons for caution This retrospective cohort study can only provide evidence of association but not causation. Also, our study results are hospital-based diagnoses of respiratory morbidity which most likely represent acute and severe disease. Wider implications of the findings In this large retrospective cohort study of siblings, we showed that, in