The number of women undergoing fertility treatment continues to rise, as do success rates, the latest UK figures show.
IVF accounts for nearly a fifth of multiple births in the UK
There was a 6% rise in the number of women having IVF, from 30,861 in 2004 to 32,626 in 2005, resulting in the delivery of 11,262 children.
The Human Fertilisation and Embryology Authority said multiple births continued to be a concern.
In 2005, 24% of IVF births were a twin or a triplet, up from 22.7% in 2004.
Twins and triplets tend to be born earlier, and so face far greater health problems.
Although IVF accounts for only around 1% of all UK births, it accounts for nearly a fifth of the multiple births in the country.
On Tuesday, the HFEA announced a three-year strategy aimed at bringing down the multiple birth rate.
The HFEA wants clinics to look at ways of cutting the rate to one in 10 or less.
The overall live birth rate for all IVF was 21.6%, up from 2004 when the figure was 20.6%.
For women under 35, the rate was 29.6%, up from 28.1% in 2004.
The HFEA also issued a new Find a Clinic section on its website, where patients can find details of treatments on offer at each clinic as well as success rates.
UK's top 10 fertility clinics for live birth rate (women under 35
using their own fresh eggs for IVF and ICSI - intra
cytoplasmic sperm injection)
Assisted Reproduction and Gynaecology Centre London - 60.7%
Lister Fertility Clinic London - 43.1%
Centre for Reproductive Medicine Bristol - 42.2%
Reproductive Genetics Institute London - 42%
UCH London - 41.1%
Centre for Assisted Reproduction (Gateshead) - 38.9%
Edinburgh Assisted Conception Unit - 38.4%
The Woking Nuffield Hospital - 38%
Nurture University Hospital Nottingham - 36.8%
St Jude's Women's Hospital Wolverhampton - 36%
It is estimated that one in seven UK couples - 3.5m people - have difficulty conceiving.
Alan Doran, interim chief executive of the HFEA said: "Good and comprehensive information is vital for any patient making choices about their treatment options.
"Statistics are just one of the many things patients need to consider when choosing a clinic.
"Their age, location, which treatments are available and what the clinic offers to support them are also absolutely key to helping them make informed decisions."
Dr Allan Pacey, of Sheffield University and the British Fertility Society, said: "The improved success rate of IVF is good news, but it is a double-edged sword because it goes hand in hand with the multiple birth rate.
"We need to do all we can to lower the multiple birth rate."