Reacción a "Babies born through assisted reproduction have increased risk of serious heart defects, study finds"

The increasing prevalence of infertility problems in the general population has led to a higher demand for assisted reproductive technologies (ART), which has raised more concerns about the health of children born through these techniques. One of the conditions most commonly associated with these techniques is heart disease. Congenital heart defects are the most frequent congenital defects and account for approximately 50% of all major congenital defects, affecting about 1%–2% of children in the general population. Heart defects are a major pediatric health issue and remain the leading cause of mortality from congenital defects. 

Several studies have been published showing an association between congenital heart defects and assisted reproduction (Olson et al., 2005v; Liu et al., 2015). Gullo et al., in 2023, conducted a meta-analysis of 24 studies to examine the relationship between heart defects in children born through ART compared to spontaneous births. They found a slight risk of congenital heart disease in pregnancies conceived via assisted reproductive technologies compared to spontaneous pregnancies. However, they concluded that this risk is not clinically significant. Other studies, such as Wen et al., only link this condition to multiple pregnancies, and in some cases, no association was found (Rasouli et al., 2024). 

The work by Sargisian et al., published today in one of the most prestigious medical journals, European Heart Journal, uses national data from four Nordic countries (Denmark, Finland, Norway, and Sweden) to evaluate the risk of major congenital heart defects in live-born children conceived through assisted reproductive technologies compared to children born after spontaneous conception. 

This large population-based cohort study of 7.7 million live-born children includes 171,735 born through assisted reproductive technologies. 

The main findings were that ART was associated with a higher risk of major congenital heart defects (CHD) and severe congenital heart disease in live-born children followed up to 1 year of age, compared to spontaneous conception (SC). Children born from multiple pregnancies had the highest risk of congenital heart disease, but ART was also associated with a higher risk in singleton fetuses. No significant difference was found between singleton fetuses born after intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF) or between fresh and frozen embryo transfers. 

Major congenital heart defects: diagnosed up to the first year in 3,159 children born after ART (1.84%) and in 86,824 children born after spontaneous gestation (1.15%). Severe congenital heart disease was detected in 594 children born after ART (0.35%) and in 19,375 children born after spontaneous births (0.26%). 

Severe congenital heart disease was detected in 0.31% (n = 399) of singleton fetuses born after ART and in 0.25% (n = 18,539) of singleton fetuses born after spontaneous gestation. In multiple births after ART, the prevalence of severe congenital defects was 0.44%, compared to 0.43% in spontaneous births. 

The main relationship with heart defects was pregestational diabetes. 

The main strength of this study is the large population size, with data pooled at the national level and cross-referenced from several high-quality national registries. Additionally, the relationship between different assisted reproductive technologies and congenital heart disease was explored, and a very robust statistical analysis was employed. 

However, there are some important limitations. First, confounding factors like maternal age and male infertility –previously linked by other authors to an increased risk of congenital heart disease– must be considered. Additionally, as the authors themselves mentioned in the study, the relationship found between heart defects and pregestational diabetes is noteworthy. However, the most important limitation is that, although the risk of major congenital heart disease is higher in children born after assisted reproductive therapy, Sargisian et al. acknowledge that the absolute increase in risk appears modest and therefore not clinically significant. In fact, the risk found in children born after ART, at 1.84%, does not exceed the general population risk, which is between 1% and 2%. 

Despite this, this information should be conveyed to patients receiving counseling before undergoing assisted reproductive therapy. This study also highlights the importance of single embryo transfer to avoid the higher risks associated with multiple pregnancies. 

Future studies should focus on the underlying infertility issues rather than the assisted reproductive techniques themselves to further explore any plausible relationships between these factors and congenital heart disease.