A study in the Netherlands has shown that lying down following artificial insemination, also known as intrauterine insemination (IUI), increases the chances of pregnancy by 50 per cent.

The findings, published in the British Medical Journal (BMJ) last week, revealed that 27 per cent of women who remained in a supine position following treatment for 15 minutes achieved a live birth, compared with only 17 per cent of those who got up and moved around. In total, 391 couples aged between 18 and 43 took part in the study, which took place across several hospitals in the Netherlands. Each couple received up to three cycles of insemination and were split into two groups - one remained immobilised immediately after treatment and the other, the control group, were asked to walk around.

Lead author Dr Inge Custers, from the Academic Medical Center in Amsterdam, said that the pregnancy rate for the immobilised group was 'significantly higher'. He explained that 'immediate mobilisation might cause leakage [of the sperm]', which may take longer to reach the fallopian tubes if the woman is moving around. 'As immobilisation is easily done and carries very little cost, we suggest incorporating immobilisation as a standard procedure in intrauterine insemination treatment', said Custers, adding that clinics in the Netherlands were already adopting the method. However, there is concern that extending the period each bed is used in clinics could mean that clinics treat fewer patients. Custers said that improving the success rate of IUI will be more economical for patients. 'Although immobilisation takes more time and occupies more space in busy rooms, the intervention will be economic in the long run, as pregnant patients will not return in subsequent cycles,' he said.

In an editorial piece which accompanied Custer's publication in the BMJ, Professor William Ledger, from the Academic Unit of Reproductive and Developmental Medicine at the University of Sheffield, said that there remain many unexplained factors that need to be explored, such as the optimal length of time a woman should remain immobile following treatment to achieve pregnancy. He also noted that it was not clear what proportion of women in the study were given drugs to stimulate their ovaries to produce eggs and expressed some doubt over the benefits of remaining immobile. 'Such postcoital positioning was advocated in the United States many years ago but did not seem to improve conception rates after sex,' he said. He also warned that the overall pregnancy rate achieved in the study is somewhat lower than can be expected in Britain.

Ledger said that clinics should perform their own studies in the 'real world' to test Custers' findings. If further studies confirm the findings of the Netherlands team then he agreed that some couples will be spared the cost of IVF (in vitro fertilisation). Artificial insemination is cheaper than IVF and requires minimal drug treatment. It is often used prior to IVF and success rates vary from 5-70 per cent, according to Ledger.