The scientists said the increasing use of IVF "may have come at a price". Picture: Pexels

London - Thousands of children born each year by IVF could be at risk of serious heart problems in later life, a study suggests.

Scientists found signs of "premature vascular ageing" in children as young as 11 who had been conceived as a result of fertility treatment.

And by the age of 16 IVF children were six times as likely to have high blood pressure – a major risk factor for heart attacks and strokes.

The scientists said the increasing use of IVF "may have come at a price".

Researchers from University Hospital in Bern, Switzerland, believe the problems are rooted in the process by which embryos are fertilised and manipulated before being implanted.

They think this may cause subtle alterations to the unborn baby’s genes. Those "epigenetic" changes could alter the way the heart and circulatory system develops, accelerating ageing.

However, other experts stressed that other cardiovascular risk factors, such as a poor diet and lack of exercise, had a much greater effect on heart health.

The Swiss team tracked 54 seemingly healthy children who had been born via IVF, and compared them to 43 children born naturally. They found at age 11 and 12 the IVF children had a 25 percent narrower brachial artery – the major blood vessel in the arm – and their arteries had thicker walls.

The team then tracked the children for five years. At the age of 16 and 17 the IVF children were far more likely to have developed high blood pressure.

They had an average blood pressure of 120/71, compared to 116/69 for the teenagers who had been conceived naturally.

Eight of those conceived via IVF had developed "hypertension" – the medical term for high blood pressure, involving a reading of more than 130/80. Only one of the teenagers conceived naturally had hypertension.

The study comes after research that found mice born using IVF had heart problems.

The scientists said in the Journal of the American College of Cardiology: "Assisted reproductive technology has allowed millions of infertile couples to have children. However, this success may have come at a price."

The scientists said doctors should heed the new "mechanistic insight" to prevent ‘cardiovascular risk in the millions of children expected to be conceived using these methods’.

This could involve ensuring IVF children do more exercise and eat healthily or giving them heart drugs from an early age.