A new strategy is needed to reduce the number of twin and triplet births caused by fertility treatment, says the fertility regulator.
Many twins and triplets are current born by IVF
Human Fertilisation and Embryology Authority chairman Walter Merricks said current techniques were leading to hundreds of unnecessary baby deaths.
He wants clinics to use fewer embryos - with the NHS paying for more IVF cycles to maintain success rates.
Fertility doctors say would-be parents need to know more about the dangers.
Clinics often implant more than one fertilised embryo to boost the chances of achieving a pregnancy.
This means that 40% of IVF babies are either twins or triplets - compared with approximately 1% of those conceived naturally.
Twins and triplets tend to be born earlier, and so face far greater health problems.
Up to 60% need to spend some time in neonatal units, compared to 20% of singletons.
Mr Merricks, the interim chairman of the HFEA, which regulates fertility clinics, told the British Fertility Society Winter Conference that a national strategy was needed to reduce these dangers.
He said: "Researchers have told us that in 2003 alone, the deaths of 126 IVF twins could have been avoided, had they been born as singletons."
The HFEA has been carrying out a public consultation for the past six months, and wants to see many women offered just one fertilised embryo, a step which would minimise the chances of a twin birth.
It wants to reduce the rate of multiple births to 10% of the total - perhaps by setting targets for individual clinics to meet.
Refinements in fertility treatment over the years mean that in many cases the chances of pregnancy are now as good with a single embryo.
However, the HFEA has stopped short of calling for a ban on the use of more than one embryo.
Older women, or those with certain fertility problems may still need more than one embryo implanted to stand a reasonable chance of success.
Mr Merricks said: "We are not in the business of intervening in the decisions made between a patient and their doctor or sacrificing women's chances of conception by asking clinicians to force women to have treatments that offer low chances of success."
Currently, many parts of the NHS which fund IVF offer just one cycle, and Mr Merricks said that this made would-be parents more likely to demand extra embryos to boost their single chance of having a child.
He has written to health minister Dawn Primarolo asking for fresh guidance to PCTs to increase this.
The HFEA also wants any national strategy to cover not just the fertility treatments which it currently regulates, but also treatments such as donor insemination and fertility hormone injections which also contribute to twin and triplet births.
The body which represents fertility doctors in the UK, the British Fertility Society, welcomed the results of the consultation.
Its Chair, Dr Mark Hamilton, said there was an "overwhelming case for change".
"We believe that an approach where the regulator provides clinics with targets for multiple rates, expressed as a percentage of all pregnancies created, is sensible, allowing clinics themselves to determine how best to reform practice to achieve this end.
"There is an urgent need for an adequately resourced public education initiative to promote effective and safe embryo transfer policies."
The Twins and Multiple Births Association (TAMBA), which offers support to the parents of twins and triplets, has already expressed concern about any changes.
Its chief executive Keith Reed said last week: "Instead of enacting new guidance which will potentially reduce patients' chances of conceiving, they must first work with the government to ensure publicly funded treatment is more widely available.
"If they carry through their plans, then they could shatter the dreams of thousands of patients."
Keith Reed, chief executive of the Twins and Multiple Births Association (TAMBA), said any decision to avoid a blanket ban on the use of more than one embryo represented a "victory" for patients.
"Retaining some flexibility over the choice that parents make is vital - and the HFEA is to be congratulated for raising the issue of NHS funding with the government."