Newborns with congenital heart defects tend to have a higher risk of growth restriction, which can be an independent risk factor for adverse outcomes. To date, a systematic review of the relation between congenital heart defects (CHD) and growth restriction at birth, most commonly estimated by its imperfect proxy small for gestational age (SGA), has not been conducted.
Objective: To conduct a systematic review and meta-analysis to estimate the proportion of children born with CHD that are small for gestational age (SGA).
Methods: The search was carried out from inception until 31 March 2019 on Pubmed and Embase databases. Studies were screened and selected by two independent reviewers who used a predetermined data extraction form to obtain data from studies. Bias was assessed using the Critical Appraisal Skills Programme (CASP) checklist. The database search identified 1783 potentially relevant publications, of which 38 studies were found to be relevant to the study question. A total of 18 studies contained sufficient data for a meta-analysis, which was done using a random effects model.
Results: The pooled proportion of SGA in all CHD was 20% (95% CI 16%-24%) and 14% (95% CI 13%-16%) for isolated CHD. Proportion of SGA varied across different CHD ranging from 30% (95% CI 24%-37%) for Tetralogy of Fallot to 12% (95% CI 7%-18%) for isolated atrial septal defect. The majority of studies included in the meta-analysis were population-based studies published after 2010.
Conclusion: The overall proportion of SGA in all CHD was 2-fold higher whereas for isolated CHD, 1.4-fold higher than the expected proportion in the general population. Although few studies have looked at SGA for different subtypes of CHD, the observed variability of SGA by subtypes suggests that growth restriction at birth in CHD may be due to different pathophysiological mechanisms.
Keywords: congenital heart defects; meta-analysis; population-based study; small for gestational age; systematic review.