All expectant parents worry, and for those undergoing fertility treatments, there are additional concerns about the health of their child.
But a new study finds one less thing they need to stress over – their children don't appear to be at greater risk of cancer than other children.
"These results provide reassuring evidence that children conceived as a result of fertility treatments do not have an increased risk of cancer after a median follow-up of 21 years," said study author Flora van Leeuwen. She is head of the department of epidemiology at the Netherlands Cancer Institute in Amsterdam.
There has been conflicting evidence about whether assisted reproductive technology (ART)-conceived children have an increased risk of cancer. ART therapies include in vitro fertilisation, sperm injection into an egg, or freezing of eggs or sperm for later use.
This study is the first to examine the long-term cancer risk in ART children compared with those in the general population or those naturally conceived by women with fertility problems.
The study included nearly 48 000 children in the Netherlands who were followed for an average of 21 years. Of those children, over 24 000 were conceived by ART, about 14 000 were naturally conceived, and nearly 10 000 were conceived naturally or with the help of fertility drugs, but not by ART.
During the follow-up period, 231 of the children developed cancer. After adjusting for a number of factors, the researchers concluded that ART-conceived children did not have an increased risk of cancer.
The study was published in the journal Human Reproduction.
Some measure of risk
"This study, with a median follow-up of 21 years, is especially important because it includes a comparison group of naturally conceived children born to subfertile women," said van Leeuwen. "These women are different from the general population, and it is possible that difficulty in conceiving could be a factor that influences the risk of cancer in their offspring."
But not every fertility treatment came without some measure of risk.
"Cancer risk was somewhat increased, although not statistically significantly so, in children conceived after intracytoplasmic sperm injection [ICSI] or from embryos that had been frozen before being thawed and used for fertility treatment," van Leeuwen said in a journal news release.
"These are two types of fertility treatments that are used more often nowadays. We also found a slightly increased, statistically insignificant, risk of lymphoblastic leukaemia and melanoma. As the numbers of cancers in these groups were small, these findings may be due to chance and must be interpreted with caution," van Leeuwen said.
"However, as ever more children are born through ICSI and cryopreservation of embryos, the long-term cancer risk should be investigated in larger numbers of children born as a result of these techniques," van Leeuwen said.
She noted that her research team is already conducting larger studies on the issue.
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