A report from the Office for National Statistics (ONS) shows that the number of multiple births among women over 45 has increased by 23 percent in the past year. The increase is thought to be in part due to more older women using IVF treatment to conceive, says the Telegraph.

The finding represents an increase from 9.9 percent to 11.6 percent of all births among women over 45. In all other age groups, the incidence of multiple births fell; multiple births are almost four times as likely in women over 45 than in the second highest age range.

IVF treatment becoming more widespread is thought to have had an impact. The largest increase was recorded between 1990 and 1995 when the rate rose by 22 percent and this coincides with when IVF treatment became more common. There is a significantly increased risk of multiple births following IVF, and this presents health risks to the mother and child.

The link between IVF treatment and multiple births has been a cause of concern for the HFEA (Human Fertilisation and Embryology Authority), which has set targets to gradually reduce the incidence of such births.

However, its maximum multiple birth rate policy for clinics has recently been the subject of a High Court ruling that decided that the HFEA's actions towards two clinics over a licence condition to impose a maximum multiple birth rate were unlawful (reported in BioNews 731). It has since announced that it will withdraw the requirement to meet the maximum birth rate target from clinics' licence conditions.

The National Institute for Health and Care Excellence (NICE) has also sought to help further reduce the numbers of multiple births by updating its fertility guideline to include advice on how many embryos should be transferred to a patient.

The guideline, which is not mandatory, continues to take into account several factors, including the patient's age and the quality of embryos available, but encourages single embryo transfer where advisable. However, for women aged between 40 and 42 it advises to 'consider' double embryo transfer but to use single embryo transfer where a top quality blastocyst is available. It recommends IVF on the NHS for women up to 42 years old, in certain circumstances, but women over 42 years old may still be accepted by private clinics for IVF.

The ONS report showed that there has been a decline of 0.2 percent in the incidence of multiple births overall.

A spokesman for the HFEA said: 'We are getting the multiple birth rate down overall. Things are moving in the right direction', reports the Telegraph.

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.