By Wendy Tuohy
Children conceived through IVF and other reproductive technologies have a significantly higher risk of serious heart abnormalities than naturally conceived children, a large international study has found.
A study of 7.7 million children in four northern European countries found babies born through assisted reproduction including IVF, intracytoplasmic sperm injection and embryo freezing have a 36 per cent higher risk of serious heart abnormalities.
Babies born via assisted reproductive technologies are more likely to have serious heart defects, a large study has found.Credit: Istock
The study, published on Friday in the European Heart Journal, found the risk of heart defects – the most common form of birth abnormalities – was particularly associated with babies born in multiple births, a practise not encouraged in Australia. Some defects cause life-threatening complications.
However, overall the risk of such defects was still low for children born through assisted reproduction: 1.84 per cent, compared with 1.15 per cent for those conceived naturally. The risk for multiples born through IVF was higher, at 2.47 per cent, compared with 1.62 per cent for those conceived naturally.
Study leader Professor Ulla-Britt Wennerholm, of the University of Gothenburg in Sweden, said previous research had identified increased risks for babies born through assisted reproduction, including pre-term birth and low birth weight.
She said the fact the risk of heart defects was similar regardless of the type of assisted reproduction used may indicate a common factor underlying the parents’ infertility and congenital heart problems in their babies.
“Congenital heart defects 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.
Factors that can increase the risk of congenital heart defects, such as a child’s year of birth, country of birth, mother’s age at delivery, if the mother smoked during pregnancy, or if the mother had diabetes or heart defects were taken into account.
Because technology is being used more widely around the world to aid conception, there may be a global increase in congenital heart abnormalities.
The University of New South Wales National Perinatal Epidemiology and Statistics Unit found in its 2023 assisted reproductive data report that a record one in 18 babies had been born in Australia through the technologies in 2021. The technologies helped with the conception of 18,594 babies.
A 2014 study by the Murdoch Children’s Research Institute found young adults conceived by assisted reproduction are just as healthy, smart and mentally stable as people conceived naturally, although they may carry a slightly higher risk of some illnesses such as asthma.
They concluded the rate of chronic illnesses, growth measures such as puberty milestones, educational achievements, and quality of life were generally similar between the naturally and medically conceived by the time they were young adults.
Fertility Society of Australia and New Zealand board member Dr Anne Clarke said the study was observational and could not be definitive in terms of cause and effect.
“The headline suggesting that IVF babies have a 36 per cent higher chance of major heart defects is misleading because the study highlights that the absolute risk is 1.84 per cent compared with 1.15 per cent in babies conceived without assisted reproductive technology (ART),” Clarke said.
Some of the births included in the study dated back to the 1980s, which made that part of the data old.
“The study also concludes that the increased risk is particularly associated with multiple births in assisted reproduction, but this is not encouraged in ART practice in Australia,” she said.
Dr Nathalie Auger, of the University of Montreal Hospital Research Centre, said assisted reproduction accounted for 2 to 8 per cent of births worldwide, and “while most neonates born after assisted reproductive technology are healthy, these procedures are not without risks”.
“Patients who use assisted reproductive technology tend to differ from the general population. These patients may have underlying morbidities that affect both fertility and the risk of heart defects,” she said.
Professor Bernard Tuch, consultant endocrinologist and director of the New South Wales Stem Cell Network, said the new data confirmed previous findings of heart abnormalities.
“It has been well documented that children born after assisted reproductive technology have a slightly but significantly increased risk of congenital abnormalities,” he said. “The commonest such abnormalities are cardiac in nature.”
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