By Steven Mew, the Australian Science Media Centre

Children conceived by IVF have no overall increased risk of childhood cancer, according to a large study of over 8.5 million children, 260,000 of whom had been born using medically assisted reproduction.

However, the study did find that there was a slightly higher risk of leukaemia among those born by fresh or frozen embryo transfer. The authors, led by Dr Paula Rios from the French National Agency for Medicines and Health Products Safety write that "this risk, although resulting in a limited number of cases, needs to be monitored in view of the continuous increase in the use of assisted reproductive technology."

Professor Jackie Leach Scully from the University of New South Wales, who was not involved in the research, said over the last half century an increasing number of children have been born through some form of assisted reproductive technology and it is important to be confident that the technologies themselves do not lead to significant health issues.

"Using any health intervention ethically depends on assessing the balance of benefits and harms," she told the AusSMC.

So, what is the risk of a child developing cancer? How do we weigh up the balance of benefits and harms as Prof Leach Scully suggests?

Quoting statistics from the Australian Institute of Health and Welfare, Associate Professor Alex Polyakov from the University of Melbourne told the AusSMC that the chance of a child developing cancer before age 14 is very low, so even a statistically significant variation will likely still mean there is a very low rate of cancer overall.

The study in question found that out of over 8.2 million children who were conceived naturally, there were 2083 cases of acute lymphoblastic leukaemia (ALL), which is roughly 2.5 cases per 10,000 children.

In the group of children who were conceived by frozen embryo transfer, there were 20 out of 66,165 who were diagnosed with acute lymphoblastic leukaemia, which is a rate of around 3 per 10,000 children.

According to Assoc Prof Polyakov, although this difference was statistically significant, there are some peculiarities inherent in this type of research which means that it is impossible to establish that frozen embryo transfer is the cause of the increase in the rate of acute lymphoblastic leukaemia.

"This is mainly because this study was retrospective in nature, and not all variations between people undergoing IVF and those who conceived naturally can be taken into account."

"Some examples of such factors, which were not included in the analysis but could have played a role in the risk of developing ALL in the offspring, are parental smoking, paternal age, and the reason for infertility, just to name a few."

"Therefore, statistically significant findings of this type of research must be interpreted with extreme caution," he said.

The main message here then, is that more research is required.

According to Professor Jackie Leach Scully, it’s understandable that families with children born using ART or who plan to use ART may have concerns.

"Further research should clarify as soon as possible whether there is a real problem and if it can be avoided so that people wanting to use these technologies can make an informed choice," she said.

You can read the full AusSMC Expert Reaction here.

This article originally appeared in Science Deadline, a weekly newsletter from the AusSMC. You are free to republish this story, in full, with appropriate credit.

Contact: Steven Mew

Phone: +61 8 7120 8666

Email: info@smc.org.au