Commonly used fertility drug useless

British scientists say that using the drug Clomid for the treatment of unexplained infertility is no more effective than no treatment at all.

The researchers have found that Clomid (clomifene citrate) was of no use to couples trying to conceive and say people in such situations should use methods such as in vitro fertilisation (IVF).

Infertility is unexplained in a quarter of all couples with fertility problems and Clomid is used in fertility treatment to induce regular ovulation by stimulating the ovaries.

The study which was conducted across five hospitals in Scotland, tracked the progress of 580 couples recruited between September 2001 and September 2005 who had been infertile for at least two years.

They were randomly assigned either to receive no treatment beyond advice about the timing of intercourse, a course of Clomid, or the intrauterine insemination (IUI) without the ovary-stimulating injection.

Couples were given general advice regarding the need for regular intercourse, but no specific measures such as basal temperature charts or luteinising hormone kits were recommended.

The three groups were comparable in terms of women's age, men's age, BMI, semen variables and proportion of couples with primary infertility, only a few individuals had endometriosis or mild male infertility problems.

The women were followed up for six months and a pregnancy test was performed two weeks after intrauterine insemination or (in the absence of a period) by day 28 in the other groups.

Women who became pregnant but later miscarried within six months of randomisation were allowed to have further treatment in their randomised groups for the rest of their allocated time.

Professor Allan Templeton, who led the research says Clomid actually seemed to slightly reduce a couple's chances of success and the study results challenge current practice, where couples are required to try such treatment before being offered IVF or other approaches.

Experts in Australia say the research confirms their own observations but Clomid can help women with polycystic ovarian syndrome.

The research is published in the British Medical Journal.