School Age Developmental Outcomes of Children Conceived by IVF Compared with Controls: A Population Linkage Study

Abstract

Background: There has been increasing interest in assessing longer term developmental and health outcomes in IVF-conceived offspring compared with those born after natural conception. So far, the findings have been conflicting. The Australian Early Developmental Consensus (AEDC) assesses children in their first year of primary school across five domains; physical health and wellbeing, social competence, emotional maturity, language and cognitive skills, and communication skills and general knowledge. Aim: To compare school entry (5-7 years of age) outcomes in IVF-conceived children in Victoria with naturally conceived controls. Method: We undertook a statewide data linkage study, with perinatal data (births 2005-2014) linked to data from major IVF providers in Victoria and the AEDC. Our approach to analysis included: complete case analysis, multiple imputation of missing data, consideration of clustering (siblings) and inverse probability weighted modeling to adjust for covariates. Our primary outcome was an AEDC score indicative of developmental vulnerability in two or more domains. We adjusted for the child’s age at assessment, sex, highest level of maternal education, maternal age, parity, SEIFA (Socio-Economic Indexes for Areas) quintile, language background other than English, and Aboriginal and Torres Strait Islander (ATSI) status. Results: The linked dataset comprised 163,418 children, including 4,441 IVF-conceived children. The IVF conceived population had older, more highly educated mothers who lived in more affluent areas and were less likely to be from non-English speaking backgrounds or identify as ATSI. IVF-conceived children were less likely to be developmentally vulnerable, in both unadjusted (RR 0.59, 95%CI: 0.52-0.67, p<0.001) and adjusted analyses (aRR 0.72, 95%CI: 0.58-0.88, p<0.001). Conclusion: Children conceived by IVF were less likely to be developmentally vulnerable in their first year of schooling, compared with peers conceived naturally. Further research should aim to understand if similar patterns are seen in other education and health domains and the potential mechanisms for these differences.