Researchers from the Danish Cancer Society and the University of Southern Denmark are investigating whether the methods used in fertility treatment may affect children's health.
One possible explanation is the hormone therapy women receive during treatment. Some receive both progesterone and estrogen, while others receive only progesterone.
The researchers also plan to investigate whether freezing and thawing fertilised eggs could play a role, according to Berlingske.
More than one million children
The study, published in the scientific journal JAMA, includes more than one million children born in Denmark between 1996 and 2012.
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The researchers followed the children until 2023 to determine how many developed cancer.
According to Berlingske, senior researcher Marie Hargreave from the Danish Cancer Society emphasises that the findings do not prove that fertility treatment causes cancer.
Other factors, such as the parents' fertility problems, may also play a role.
Two methods stand out
The study shows that approximately 18 out of every 100,000 children conceived without fertility treatment develop cancer each year.
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The researchers found no increased risk associated with conventional in vitro fertilisation (IVF) using fresh eggs.
However, among children conceived through intracytoplasmic sperm injection (ICSI), a procedure in which a single sperm cell is injected directly into an egg, the rate was 28 cancer cases per 100,000 children per year.
The highest rate was found among children born following treatment using frozen fertilised eggs, with 41 cases per 100,000 children per year.
This means that the two methods are associated with an increased risk of childhood cancer.
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However, the researchers stress that childhood cancer remains rare and that the findings require further investigation.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.