Children born as a result of fertility treatment appear to be much more likely to have asthma, a new study suggests.
UK scientists looked at those taking part in an ongoing study of children born between 2000 and 2002. Almost 19,000 children are involved and it is one of the few large studies that include details about conception and asthma.
An estimated one in 10 couples have problems conceiving naturally and many of these will opt for some form of fertility treatment,
The team found that the children of sub-fertile parents were much more likely to have asthma and to be taking anti-asthmatic medication at the age of five.
Sub-fertile refers to people who either took longer than a year to conceive naturally, or who used some form of assisted reproduction technology (ART).
The link seemed to be most associated with children born after IVF (in vitro fertilisation) or (ICSI) intracytoplasmic sperm injection. In fact, these children were up to four times more likely to have asthma, wheezing or be taking asthma medication by the age of five.
Overall, those born to sub-fertile parents were 39% more likely to have asthma and 90% more likely to be taking anti-asthma medication by the age of five, compared to children who had been planned and conceived naturally in less than a year.
"Although we found an association, we cannot tell at this time if it is causal. Further research is needed to establish what might be causing the association and the underlying mechanism involved. It is also important to remember that for most children, asthma is a manageable condition and shouldn't prevent children from living a full and active life," the scientists based at the universities of Oxford and Essex said.
They suggested a number of possible reasons for the apparent link such as the severity of the infertility and an over-reporting of asthma symptoms by over-protective ART parents, although the scientists think this is unlikely.
They plan to continue to monitor the children to see if the same effect is present at the age of 11.
Details of these findings are published in the journal, Human Reproduction.
Asthma is a very common inflammatory lung disease affecting 470,000 people in Ireland, including one in every five children. For more information on the condition, see our Asthma Clinic here