By Deborah Condon

The continuing high rate of multiple pregnancies amongst women who have undergone assisted reproduction, such as in-vetro fertilisation (IVF), is cause for major concern and the incidence of such pregnancies must be reduced, a major European conference on reproduction has been told.

IVF is the name given to a technique where eggs are fertilised with sperm outside the body in a test tube. The resulting embryo is then placed back into the woman's uterus.

Many countries, including Ireland, transfer more than one embryo at a time in order to increase the chances of a pregnancy. The natural rate of multiple births is around 1%, however where a pregnancy results from assisted reproduction, the rate rises to 20-40%.

Speaking at the annual conference of the European Society of Human Reproduction and Embryology (ESHRE), Dr Karl Nygren, a professor of obstetrics in Sweden, said that the high rate of multiple pregnancies is a 'major medical, psychosocial and economic problem'.

Dr Nygren said that the push for multiple pregnancies was driven by a combination of factors, including costs and patients' wanting 'to meet their reproductive goals as quickly as possible'.

"The reasons for multiple pregnancies is the drive to maximise effectiveness. However evidence is accumulating that that a policy leading to multiple births means increased risk of prematurity and consequently, higher mortality, disability and ill health", Dr Nygren said.

There are also 'psychosocial' problems, such as more difficult pregnancies and more caesarean sections, he added.

He recommends transferring only one embryo to the uterus during IVF.

The ESHRE conference is taking place in Vienna.