Children conceived through fertility treatment are on the whole at no greater risk of developing childhood cancers, a new and largest of its kind study has found.
The study, conducted by the impartial Cancer Research UK, saw researchers examine the medical records of some 106,013 children up to the age of 15 who were born in the UK between 1992 and 2008. All those children were conceived through in-vitro fertilization (IVF). Their records were then checked against medical reports from the National Registry of Childhood Tumours to give comparable data for those age ranges.
For a sample of this size, the researchers expected that around 110 children would develop a childhood cancer, the most common types being leukaemia, neuroblastoma, or retinoblastoma, among others. In fact, only 108 children in the IVF sample developed a cancer, slightly lower than the prediction but of course not of any real statistical significance.
Previous studies had shown a possible link between IVF and an increased risk of childhood cancers, though those studies involved much smaller sample sizes and, even in those cases, the risks were not attributed to the IVF techniques themselves but other factors like underlying genetic problems that could be traced back to the parents. As such, this latest study helps clarify that IVF techniques appear safe.
“Our findings suggest that children conceived with IVF techniques have no greater risk of childhood cancer overall than naturally conceived children,” the author of the study Dr. Alastair Sutcliffe is quoted as saying. ”[This study, which is] bigger than all the existing studies, has a powerful and reassuring message to families, fertility specialists and the public,” Sutcliffe added. “Namely that in a near 100 percent coverage of 106,000 children conceived with IVF, the rate of childhood cancer was almost identical to that of the naturally conceived children over the same time frame.”
The research, published in the New England Journal of Medicine, provides one of the first and only large scale population-based research papers into assisted conception and cancer risk, delivering important reassurances to those parents who cannot conceive without help.
Interestingly, there was a slight increase in some very rare forms of cancer: hepatic tumors and bone tumors. The researchers could not attribute this to IVF treatment itself and, in the case of what are known as hepatoblastoma, the increase was associated with low birth weight that is sometimes found among IVF children. In both cases the slight “absolute risk” increase was of very little practical consequence.
It is estimated that around five million children throughout the world are born as a result of IVF. The (natural cycle) IVF technique has been in successful use since 1978, with UK resident Louise Brown being the first so-called “test tube baby.”
Ever since those first births, there has been speculation, usually by those opposed to IVF on religious grounds or sensationalist media outlets, that this and other forms of assisted conception carry health risks for the children involved because of the various degrees of manipulation needed to ensure conception is successful. There is of course also a genuine medical interest in ensuring that the procedure is safe and doesn’t produce unintended health problems.
In reality, no research has ever been able to find a concrete link between the IVF process and most childhood health problems. In cases where IVF children appear more prone to certain, usually rare, conditions, a link can usually be made to the same genetic problems that led to the child’s parents having trouble conceiving.
Some research has suggested that genetic expression may slightly differ during IVF as opposed to normal conception and that this in turn might in a small number of cases produce an increased risk of certain genetic disorders and birth defects — but again, this research is by no means conclusive and the topic is undergoing further study.
Researchers not directly involved with this latest study have greeted the results as reassuring to those seeking IVF, with Dr. Lawrence Grunfeld, of the Mount Sinai Icahn School of Medicine in New York City, quoted as saying, “This study is extremely reassuring and should relieve anybody’s anxiety about IVF.”
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