Thousands of children born each year from IVF could be at risk for asthma.
Researchers found that IVF increases the risk of childhood asthma by 22 percent.
Scientists at the Norwegian Institute of Public Health, tracking more than 500,000 children, believe that the drugs given to mothers during the IVF process can cause asthma in their children.
A study by the Norwegian Public Health Institute found that more than 550,000 IVFs were significantly more likely to suffer from asthma due to medication Children
Manipulating the way embryos are handled before they are implanted in the womb could also play a role, they said.
Worldwide, more than 8 million children have been born via IVF since the technology was introduced to the United Kingdom 40 years ago.
In the UK alone 20,000 children are born with IVF each year. The number is closer to the 60,000 mark in the US.
Experts have repeatedly rejected the fear that children born this way could be in poor health later in life.
They often argue that there are health consequences more likely to be associated with the underlying infertility of a mother than with the IVF itself.
The Norwegian scientists, whose work is published in the BMJ journal Thorax, claim that they have shown that asthma is partly related to fertility problems in a mother. Much of this is due to the IVF procedure itself.
Initially, they found that children born with IVF were 42 percent more likely to develop asthma at the age of seven than children who were naturally conceived.
19659015] Asthma is a common but incurable disease that affects the small tubes in the lungs.
It can lead to inflammation or swelling, which restrict the respiratory tract and make it difficult to breathe.
The disease affects people from all ages and often begins in childhood. The symptoms may improve or even disappear as the children get older, but they can recur in adulthood.
Symptoms include wheezing, shortness of breath, chest tightness and coughing. These can worsen in an asthma attack.
The treatment usually involves medication
Triggers for the disease include allergies, dust, air pollution, exercise and infections such as cold or flu.
If you think you or your child has asthma, you should see a doctor because it can lead to more serious complications, such as tiredness or lung infections.
But then they compared the IVF children with those born naturally but whose parents had taken more than 12 months to conceive.
They found that the additional risk of asthma was lower, but still remained at 22 percent, suggesting that half of the risk was due to fertility problems and half to the IVF procedure.
She wrote: "Several steps in assisted reproductive technology treatment may alter the natural course of fetal development.
" For example, medications used to induce ovulation and ensure that pregnancy is maintained in the early stages However, the nature of the medium used for culture freeze and thaw cycles, the possibility of polyspermic fertilization, the hormonal environment and / or the manipulation of the embryo. "
British experts, however, criticized the study last night, stressing that the authors have important aspects how parents' smoking did not take into account.
Professor Alastair Sutcliffe of University College London said: & # 39; The study had no access to major confounders such as paternal smoking cessation.
"The proposed mechanistic link between asthma and assisted conception is wrong u nd implausible in my view.
"This study must be viewed as largely speculative and unconvincing.
"The rates of" asthma "were implausibly low, suggesting an error in the definition of" asthma. "Jane Stewart, chair of the British Fertility Society, said," Although this study raises some interesting questions, there are many variables that play a role in both infertility and the development of asthma. "
some causal relationship. & # 39;