NI BabyHearts 2 study protocol: Examining preconceptional and antenatal factors in relation to developmental and educational outcomes of children with and without congenital heart disease NI BabyHearts 2: Study Protocol

Background Congenital heart disease is the most common congenital anomaly and a major public health concern. No single cause has been identified, and its aetiology is most likely to be multifactorial, determined by a combination of genetic and environmental factors. Congenital heart disease can have a significant and lasting impact on childrens health and development with well documented neurodevelopmental difficulties experienced by some children with CHD. However, evidence linking early environmental factors to developmental outcomes remains limited, despite growing recognition of their importance. The Northern Ireland BabyHearts 2 Study provides an opportunity to investigate these relationships in a longitudinal cohort with extensive prospectively collected preconceptional and antenatal data. Aim To investigate the associations between preconceptional and antenatal environmental factors and the birth outcomes, physical health, neurodevelopment and academic achievement of children with and without congenital heart disease. Methods This is a longitudinal matched cohort follow-up study of children with and without congenital heart disease recruited to the NI BabyHearts 1 case-control study (2014-2017), with controls matched 1:1 by age and sex. Data sources include the existing NI BabyHearts 1 dataset of prospectively collected preconceptional and antenatal environmental exposures, together with linked routine maternity and prescribing data. Follow-up data collected at 8-11 years of age include parental questionnaires assessing child executive function and behavioural development, standardised child-completed assessments of neurodevelopment, language and educational attainment, and clinical information. Impact This study will provide evidence on the long-term health and developmental outcomes in children born with and without congenital heart disease and improve understanding of how early environmental factors influence these outcomes. Findings will inform clinical care and service provision for children with congenital heart disease, strengthen preconception and antenatal guidance, and contribute to public health policy aimed at improving long-term outcomes for children living with congenital heart disease.