Scientists estimate that 12 million babies have been born as a consequence of vitro fertilization (IVF) and other reproductive technologies. All over the world, IVF is an especially popular treatment for adults struggling to conceive naturally. But stark new research has now warned of a dangerous potential consequence of the treatment.

The study, led by Sweden's University of Gothenberg, claimed that babies born this way are 36% more likely to experience a major heart defect. This threat is particularly increased in circumstances of of twin and triplet births which reportedly occur in 11% of IVF pregnancies compared with 1-2% of natural conceived pregnancies, according to Twins Trust . Professor Ulla-Britt Wennerholm, who led the project, told ScienceDaily : "We already know that babies born after assisted reproductive technology have a higher risk of birth defects in general however, we have found a higher risk also in congenital heart defects, the most common major birth defect.

"The fact that the risk of heart defects is similar regardless of the type of assisted reproduction used may indicate that there is some common factor underlying infertility in parents and congenital heart disease in their babies." Mayo Clinic explains that congenital heart defects occur due to a problem with 'the structure of the heart that a child is born with'. While some infants don't need treatment, others may experience more complicated or even life-threatening issues.

As part of the study, sc.