Babies born after infertility treatment are more likely to have asthma at age five than children conceived naturally, according to findings based on the Millennium Cohort Study.
Researchers from the University of Oxford and the University of Essex found that at age five, children born to “sub-fertile” parents – those who conceived after more than a year of trying or by some form of infertility treatment – were significantly more likely to suffer from asthma or wheezing, or to take anti-asthmatic medications. In vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) babies were the most likely to suffer from these conditions. IVF and ICSI children were 39 per cent more likely to have asthma, 27 per cent more likely to wheeze, and 90 per cent more likely to be taking asthma medications. The association remained even after controlling for a range of potential confounding factors, including mother’s history of asthma, smoking, body mass index, socio-economic status; whether there were any furry pets in the household, and premature births.
However, it is not clear from these findings that IVF or other treatments cause asthma, and researchers say that parents using assisted reproduction technology (ART) should not be worried. Dr Claire Carson, of the National Perinatal Epidemiology Unit at the University of Oxford, said: “Although the children born after ART were more likely to be diagnosed and treated for asthma than other children, it is important to remember that in absolute terms the difference is quite small. Fifteen per cent of the children in our study had asthma at the age of five. Although this figure was higher, 24 per cent, in the IVF children, it isn’t much higher than the one in five risk for all children in the UK.”
The Millennium Cohort Study (MCS) follows nearly 19,000 children born in the UK in 2000-01. It is one of the few large observational studies that includes data on conception methods and asthma, as well as other factors such as social circumstances and lifestyle. This particular research analysed data from 104 babies born after some form of ART treatment. The researchers intend to follow up the MCS children when the data from the ongoing age 11 survey becomes available.
Carson, C., Sacker, A., Kelly, Y., Redshaw, M., Kurinczuk, J.J., and Quigley, M.A. (2012) Asthma in children born after infertility treatment: findings from the UK Millennium Cohort Study. Human Reproduction, advanced online access.