- Design
- Systematic review and random-effects meta-analysis of 13 observational studies
- Population
- About 45.9 million births, 4986 conceived by assisted reproductive technology
- Primary outcome
- Study-defined incidence of major congenital heart defects
- Effect
- RR 2.35 (95% CI 1.68 to 3.28), significant heterogeneity
A meta-analysis in the Journal of the American Heart Association pooled 13 observational studies comparing congenital heart defects after assisted reproductive technology with spontaneous conception. The total population was very large, but only 4986 children had been conceived by assisted reproduction.
Assisted conception was associated with a higher risk of major congenital heart defects (RR 2.35, 95% CI 1.68 to 3.28), with significant heterogeneity between studies. Tetralogy of Fallot, ventricular septal defect and atrial septal defect were each more frequent; other defects, including transposition and hypoplastic left heart, showed no difference.
The association cannot separate the technology from the reasons for needing it — older parental age, subfertility itself, multiple pregnancy and maternal comorbidity all travel with assisted conception. It does support paying close attention to the fetal heart at the anomaly scan in these pregnancies.
- Record the mode of conception at booking so the anomaly scan team knows the pregnancy followed assisted reproduction.
- Check that the mid-trimester scan includes the outflow tracts and septa, where the excess defects in this analysis clustered.
- Consider referral for fetal echocardiography where views are incomplete or any cardiac finding is uncertain after assisted conception.
- When counselling couples before treatment, describe the risk as a possible association, not an established effect of the procedure.
Why it matters
A finding that the excess clusters in septal and outflow defects tells the sonographer where to look.
Don't overread it
This pools observational studies with high heterogeneity; it shows an association, not that the procedure itself causes heart defects.
The statistics, in plain English
A risk ratio of 2.35 means heart defects were reported a little over twice as often after assisted conception. Because the baseline rate of major defects is low, the absolute increase is small. Significant heterogeneity means the studies disagreed on the size of the effect, so the single pooled number is less certain than its interval suggests.
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