The NHS is having to pick up the pieces of couples travelling abroad for treatment where they often return pregnant with twins or triplets.

Multiple pregnancies are the biggest risk of fertility treatment and the chances of high blood pressure, admission to hospital, premature labour, disabilities in the child and even death in mother or babies is higher.

In the UK fertility clinics are more likely to transfer one embryo at a time which minimises the risk of twins or triplets but many women fear this could harm their chances of success and actively seek treatment abroad where doctors are more willing to transfer more embryos into the womb, despite the risks.

New research presented on Friday at the Royal College of Obstetricians and Gynaecologists (RCOG) 7th International Scientific Meeting in Montreal has looked at the impact of higher order multiple pregnancies (triplets or above) within the NHS and the link with fertility treatment received overseas.

The study, from the Fetal Medicine Unit at University College London Hospital (UCLH), included 109 women with higher order multiple pregnancies of which 15 had conceived naturally and 94 had received fertility treatment. Of those who had fertility treatment, 25 per cent received it outside of the UK.

The reasons for overseas treatment included the cost in the UK, that the country was their home, a better success rate due to higher number of embryo transfers overseas, faster speed of treatment and the availability of an acceptable ethnic donor.

Dr Alastair McKelvey, Subspecialty Fellow in Materno-Fetal Medicine at University College London Hospital and lead author of the study, said: "Triplet, quadruplet and higher order multiple pregnancies are very challenging high-risk pregnancies. We were concerned, through personal experience, about the extent of this problem and its link to unregulated fertility care on the world market.

"The information revolution and globalisation have radically changed many aspects of life - including medicine and access to it.

"National regulatory bodies can be sidestepped by couples desperate for a baby and the myriad of tempting offers of fertility treatments can lead them to serious adverse consequences.

"This research suggests that international agreement on this aspect of women's health - preferably by professionals - is needed."