Infants born after fertility treatment face greater risk for heart defects

Key takeaways:

• Live births after ART, especially multiple births, were linked to greater risk for major and severe CHDs.
• Result showed similar CHD risk regardless of the ART method.

Infants conceived after assisted reproductive technology had a 36% greater risk for being born with a major heart defect, results from a large cohort study published in the European Heart Journal showed.

According to background information from the CDC, congenital heart defects (CHDs) affect nearly 1% of births — around 40,000 — in the U.S. annually.

“Previous research shows that there are increased risks for babies conceived with the help of assistive reproductive technology [ART],” Ulla-Britt Wennerholm, MD, PhD, an adjunct professor at the University of Gothenburg in Sweden, said in a press release from the European Society of Cardiology. “These include preterm birth and low birth weight. We wanted to investigate whether the risk of heart defects was higher for babies born following assisted reproduction.”

In the study, Wennerholm and colleagues assessed the live births of children born in Denmark (1994 to 2014), Finland (1990 to 2014), Norway (1984 to 2015) and Sweden (1987 to 2015).

Overall, the analysis included 7,747,637 total livebirths, of which 171,735 were born after the availability of certain ARTs, such as embryo freezing, intracytoplasmic sperm injection (ICSI) and in vitro fertilization.

The researchers looked at several outcomes, which included major CHDs and major CHDs classified as severe by the European Concerted Action on Congenital Anomalies and Twins.

They reported major CHDs in the first year of life for 1.84% of children born after ART and in 1.15% of children born after spontaneous conception (adjusted OR = 1.36; 95% CI, 1.31-1.41).

The results showed similar risk for CHDs regardless of the use of ICSI or IVF, or the use of fresh vs. frozen embryos.

“The fact that the risk of heart defects is similar regardless of the type of assisted reproduction used may indicate that there is some common factor underlying infertility in parents and CHD in their babies,” Wennerholm said in the release.

Major CHDs occurred in 2.47% of multiple births following ART vs. 1.62% of singleton births (aOR = 1.7; 95% CI, 1.58-1.84).

Researchers reported severe CHDs in 0.35% of children born after ART and in 0.26% of children born after spontaneous conception (aOR = 1.3; 95% CI, 1.2-1.42).

As was the case for major CHDs, multiple births following ART corresponded to a greater risk for severe CHDs compared with single births (aOR = 1.46; 95% CI, 1.22-1.75).

The study investigators identified a couple study limitations. The rates of CHD varied between countries, while there was a lack of information on CHDs in termination of pregnancies, stillbirths and miscarriages.

“CHDs can be extremely serious requiring specialist surgery when babies are very young, so knowing which babies are at the greatest risk can help us diagnose heart defects as early as possible and ensure the right care and treatment are given,” Wennerholm said in the release. “More and more people are conceiving with the help of ART, so we might expect to see increases in cases of CHDs worldwide.”

In a related editorial, Nathalie Auger, a researcher at the University of Montreal Hospital Research Centre in Canada, and colleagues explained that ART accounts for 2% to 8% of births depending on the country, although “these procedures are not without risks.”

They highlighted several possibilities as to why birth defects are more prevalent among births following ART, pointing out that patients who use ART often have enhanced prenatal care “and possibly more detailed ultrasounds that increase the chance of detecting heart defects.”

“The next direction of research will need to focus on determining if assisted reproductive technology does indeed have a direct effect on heart defects,” Auger and colleagues wrote. “Future studies will need to be carefully designed to answer this question.”

References:

• Auger N, et al. Eur Heart J Cardiovasc Pharmacother. 2024;doi:10.1093/eurheartj/ehae549.
• Babies born after fertility treatment have higher risk of heart defects. Available at: https://www.escardio.org/The-ESC/Press-Office/Press-releases/babies-born-after-fertility-treatment-have-higher-risk-of-heart-defects. Published Sept. 27, 2024. Accessed Sept. 30, 2024.
• Data and statistics. Available at: https://www.cdc.gov/heart-defects/data/index.html. Accessed Sept. 30, 2024.
• Sargisian N, et al. Eur Heart J Cardiovasc Pharmacother. 2024;doi:10.1093/eurheartj/ehae572.