Mode of Conception and Long-Term Infectious Morbidity of the Offspring; a Sibling Analysis

Aim: To investigate the association between mode of conception, that is, using fertility treatments versus spontaneously conception, and long-term infectious morbidity of the offspring while employing sibling matched analysis. Methods: A retrospective population-based cohort study was performed, including all sibling deliveries between 1991 and 2021 at a tertiary medical center. Offspring were followed until the age of 18. A Kaplan–Meier survival curve was used to compare the cumulative incidence of infectious morbidity, and a multivariable Cox survival hazards regression model was used to control for confounders. Results: During the study period, 14 336 siblings met the inclusion criteria, of which 7711 (53.8%) were conceived through fertility treatments and 6625 (46.2%) were conceived spontaneously. No differences in long term infectious morbidity were demonstrated between siblings conceived following fertility treatments and spontaneously conceived siblings using Kaplan Meier survival curve (Log-Rank p = 0.614). Likewise, the Cox proportional hazard model did not demonstrate an independent association between mode of conception and long-term infectious morbidity in the offspring (adjusted HR 0.92, 95% CI 0.85–1.00, p = 0.063) controlling for maternal age, gestational age and follow up time. Conclusion: Using a sibling analysis, fertility treatment does not appear to be an independent risk factor for long-term infectious morbidity of the offspring up to 18 years of age.