British couples travelling abroad to take advantage of commercial surrogacy arrangements are engaging in a form of 'exploitation', Professor Naomi Pfeffer, an expert in the ethics and regulation of controversial developments in medicine, said at a fertility meeting this week.

Speaking at the 'Motherhood in the 21^st Century' conference at University College London on Friday, she said: 'The exchange relationship is analogous to that of a client and a prostitute. It's a unique situation because it's the only instance in which a woman exploits another woman's body.'

In the UK women who act as surrogates for infertile couples are allowed to receive up to £10,000 to cover expenses, but any further payment is illegal. This has contributed to an acute shortage of surrogates in the UK, driving many couples to travel abroad where commercially-arranged surrogacy is permitted. In such instances, more vulnerable members of society could feel pressured to offer themselves as surrogates in order to repay debts or put food on the table, Professor Pfeffer warned. She also harboured concerns about the risks surrounding egg retrieval, which involves taking powerful hormones to stimulate egg production in the ovaries and having a needle inserted into the vaginal wall under local anaesthetic.

She said: 'Most of these women are in developing economies where access to healthcare is limited by their ability to pay. They are often vulnerable women and it's a very unequal economic relationship. These women are being encouraged to take real risks with their health through ovarian stimulation and egg retrieval. It commodifies women's bodies and treats their reproductive capacities as a service.'

Also speaking at the event, Lord Robert Winston, Emeritus Professor of Fertility Studies at Imperial College, agreed that paying for treatment abroad was 'a form of exploitation,' while Professor Sammy Lee, an IVF expert who teaches medical ethics, embryology and biomedical sciences at University College London, said that the acute shortage of egg and sperm donors in the UK would quickly lead to more couples going abroad.

In July this year Professor Lisa Jardine, Chair of the UK's Human Fertilisation and Embryology Authority (HFEA), questioned whether reversing the ban on payment for sperm and eggs in the UK would potentially allow a more transparent system of donation to be adopted.

A study, presented at the European Society for Human Reproduction and Embryology (ESHRE)'s annual conference earlier this year, indicated that each year 20,000-25,000 women from Britain are travelling abroad to access treatment which is unavailable to them at home.