The number of older women having multiple births is on the increase as couples seek fertility treatment abroad, new figures reveal.
While the multiple birth rate across all age groups has increased steadily over the past 10 years, the biggest rise has been among women aged 45 and over, say figures from the Office of National Statistics.
In 2009, 156 women gave births to twins or triplets compared to just 29 a decade earlier. It means the multiple birth rate in women over 45 has increased by 123 per cent in 10 years.
This is believed to be largely down to the rise in egg donation, where older women are implanted with the fertilised eggs donated by younger women.
In Britain, fertility clinics have been trying to reduce the multiple pregnancy rate by implanting women with fewer embryos at a time.
Multiple births are the largest single risk to pregnant women and their babies following IVF, with a greater chance of miscarriage and pre-eclampsia. Babies are more likely to be premature, have physical abnormalities and long-term health problems.
Speaking in the Daily Telegraph, Tony Rutherford, chairman of the British Fertility Society warned that if primary care trusts continued to withdraw funding for fertility treatment on the NHS then more women will seek treatment abroad at unregulated clinics and the multiple birth rate would continue to rise, despite the best efforts of British clinics.
The cost of multiple births to the NHS is much higher than for single babies because of the intensive care they often need.
A single baby costs the NHS around £3,000, twins cost around £9,000 and triplets around £32,000, the last estimates suggested.
Other data released by the ONS showed the number of women giving birth at home has dropped slightly in the last year. In 2009, 2.7 women gave birth at home, down from 2.9 in 2008.