P-769 Congenital heart defects in children born after assisted reproductive technology: A large cohort study from the Committee of Nordic Assisted Reproductive Technology and Safety (CoNARTaS)
Authors: Sargisian N , Petzold M , Furenäs E , Gissler M , Lærke Spangmose A , Malchau Lauesgaard S , Opdahl S , Pinborg A , Henningsen A  K , Westvik-Johari K , Rönö K , Bergh C , Wennerholm U  B 
Published: July 2024

Study question

Are children conceived after assisted reproductive technology (ART) more likely to be born with congenital heart defects (CHDs) than those born after spontaneous conception (SC)?

Summary answer

Major CHDs and severe CHDs are associated with ART, with a higher risk in both ART-conceived singletons and multiples compared to singletons from SC.

What is known already

Children born after ART have higher risk of birth defects compared to children born after SC. Among these defects, CHDs hold the highest prevalence, accounting for about 50% of all major birth defects and affecting approximately 1-2% of children in the general population. Several cohort studies and systematic reviews, among these a recent review including 41 studies and in total 25,856 ART children, shows increased risk of CHDs in children born after ART. However, conflicting findings have been reported for specific CHDs.

Study design, size, duration

This Nordic registry-based cohort study included 7,747,637 liveborn children, with 171,735 conceived after ART. All liveborn children (singletons and multiples) in Denmark (1994–2014), Finland (1990–2014), Norway (1984–2015), and Sweden (1987–2015) were included. National data from ART registries, medical birth registries, patient registries, cause of death registries, and population registries were cross-linked.

Participants/materials, setting, methods

The International Classification of Diseases (ICD) versions 8, 9, 10 were used for selection of CHDs. Major and severe CHDs were defined according to European Concerted Action on Congenital Anomalies and Twins (EUROCAT). Outcomes were major CHDs, severe CHDs, six hierarchical CHD lesion groups, and ten selected major CHDs. CHD diagnoses were considered prenatally or within the first year of life in Denmark, Finland, Sweden, and prenatally or at birth in Norway.

Main results and the role of chance

Major CHDs occurred among 1.84% (n = 3159) children born after ART and among 1.15% (n = 86,824) children born after SC, with adjusted odds ratio (AOR) 1.36; 95% CI 1.31–1.41. Risk was highest in multiples, regardless of conception method.

Severe CHDs were detected in 0.35% (n = 594) children born after ART and in 0.26% (n = 19,375) children born after SC; AOR 1.30; 95% CI 1.20–1.42.

When analysing the risk of CHD for the specific groups of CHDs by the hierarchical classification, children born after ART had higher risk of CHDs than children born after SC for five of the six lesion groups: conotruncal defects, non-conotruncal defects, ventricular septal defect, atrial septal defects, and other CHDs. ART was further associated with an elevated risk in four of ten selected major CHDs.

Major CHDs occurred among 1.62% (n = 2059) singletons born after ART and among 1.11% (n = 18,539) singletons born after SC; AOR 1.19; 1.14–1.24. The prevalence of severe CHDs was 0.31% (n = 399) among singletons born after ART and 0.25% (n = 18,539) among singletons born after SC; AOR 1.20; 95% CI 1.09–1.33.

In singletons born after ART, no difference was seen between ICSI and IVF or between frozen and fresh embryo transfer for major CHDs or severe CHDs.

Limitations, reasons for caution

A main limitation in this study is the lack of information on CHDs in miscarriages, pregnancy terminations, and stillbirths. Another limitation is that information on specific techniques used in assisted reproduction was not available from Finland. Lastly, we did not have information on causes of infertility.

Wider implications of the findings

CHDs, although rare, imply severe risks. Our study reveals an association between ART and major CHDs. While most CHD-affected children survive to adulthood, high morbidity and mortality rates persist in childhood and adulthood. The potential benefit of fetal echocardiography screening in ART pregnancies, beyond routine obstetric ultrasound, remains uncertain.

Trial registration number

ISRCTN 11780826