Birthweight and isolated congenital heart defects - A systematic review and meta-analysis

Background: Birthweight (BW) is an important prognostic factor in newborns with congenital heart defects (CHD).

Objectives: To give an overview of the literature on BW z-score in children with isolated CHD.

Search strategy: A systematic search was performed on isolated CHD and BW in PubMed, Embase, Web of Science, COCHRANE Library and Emcare.

Selection criteria: Neonates with isolated CHD were included if a BW percentile, BW z-score or % small-or-gestational age (SGA) was reported.

Data collection and analysis: BW z-score and percentage SGA were pooled with random-effect meta-analysis. Quality and risk of bias were assessed using the modified Newcastle Ottawa Scale.

Main results: Twenty-three articles (27 893 cases) were included. BW z-scores were retrieved from 11 articles, resulting in a pooled z-score of -0.20 (95% CI -0.50 to 0.11). The overall pooled prevalence of SGA <10th percentile was 16.0% (95% CI 11.4-20.5; 14 studies). Subgroup analysis of major CHD showed similar results (BW z-score -0.23 and percentage SGA 16.2%).

Conclusions: Overall BW in isolated CHD is within range of normality but impaired, with a 1.6-fold higher risk of SGA, irrespective of the type of CHD (major CHD vs all CHD combined). Our findings underline the association between CHD and BW. The use of BW z-scores provides insight into growth of all fetuses with CHD.

Tweetable abstract: Infants with a congenital heart defect (CHD) have a lower birthweight z-score and a higher incidence of small-for-gestational age (<10th percentile). This was encountered both in the major CHD-group as well as in all-CHD combined group analysis. Future research on the association between birthweight and CHD should include all types of CHDs (including mild cardiac defects) and placental-related disease, such as pre-eclampsia. We advocate the use of international standardised fetal growth and birthweight charts in CHD research.