Quite a handful: Newborn twins

There are calls to restrict the number of embryos put back during treatments in order to limit multiple births.

A fertility conference in San Antonio, US, heard how parents of IVF twins and triplets were much more likely to report marriage problems.

Between 20% and 40% of all IVF births involve more than one baby.

It is already well known that carrying twins, triplets or more substantially increases the risks to both mother and babies.

"Multiples" are far more likely to be born early and suffer a wide range of complications such as low birth weight, defects and disability.

Quality of life

Marcia Ellison, from Harvard Medical School in Boston, who led the study, told the American Society for Reproductive Medicine conference that the psychological impact of coping with more than one newborn was significant.

This was despite the fact a high proportion of those seeking IVF treatment were well-educated and wealthy, and able to call on a wide support network following the birth.

Women are designed to carry only one baby Spokesman, HFEA

She said: "Multiple births resulted in significant increases in unmet family needs, social stigma and higher maternal depression scores.

"In addition, multiple births resulted in significant decreases in maternal quality of life, health and functioning, satisfaction with their marriage and their husband, and lower overall quality of life scores."

Some of the women involved actually regretted ever seeking IVF treatment after having to cope with more than one baby.

In the UK, the Human Fertilisation and Embryology Authority, which regulates fertility clinics, said that it was keen to clamp down on those which put more than two embryos back into a woman during IVF treatment.

Studies have suggested that putting more embryos back does not increase the chances of a successful pregnancy, but simply raises the chances of multiple births.

Some experts favour putting only one embryo back - claiming success rates comparable with clinics that transfer two embryos.

An HFEA spokesman said: "There is general concern about multiple births because of the harm that they do to the actual babies, and the potential harm they do to the mother.