Fears that having a baby by IVF increases the risk of complications before, during and after birth are unfounded, according to a study of more than 1.2 million births.
Previous studies have suggested that children conceived artificially are more at risk of low birth weight, premature birth, stillbirth or death shortly after birth.
However, the new, more sophisticated analysis found that these extra risks are the fault of existing fertility problems in the parents and not the techniques used during IVF and other assisted fertilisation methods.
The new research used data from the medical birth registry of Norway, which contains virtually complete records of births in the country from 1988 onwards.The team compared just over 1.2 million single births with 8,229 single who were conceived by assisted fertilisation.
As in previous studies, in this crude analysis they found that children born by assisted fertilisation are around 70 per cent more likely to be premature (born before 37 weeks) and more than twice as likely to be born before 32 weeks.
Children born by IVF and other methods were also 26 per cent more likely to be small for their gestational age.
This result does not necessarily mean that IVF procedures are at fault.
The team's results are published in the Lancet.