Clomid (clomiphene) is a powerful and longstanding infertility drug but of late, research has been suggesting that it can cause birth defects.
Those at risk are women who start taking the drug without realising they are already pregnant and women who become pregnant while taking the drug. The simple solution is for all women to have a pregnancy test before and during treatment with the drug. If she has already taken the drug, her pregnancy should be monitored carefully, reports medical journal Revue Prescrire (1999; 19: 40-1).
The manufacturer states that birth defects among users who are already pregnant are no more common than in the general population, although animal tests suggested otherwise.
Foetal abnormalities that have been noted include, in order of frequency, heart lesions, Down syndrome, club foot and gut lesions.
But a pregnancy check is not the only one that should be carried out before prescribing Clomid. Women who have ovarian cysts or abnormal vaginal bleeding should not be given the drug, nor should those with abnormal liver function.
One of the most common adverse reactions to the drug is visual disturbance, such as spots or flashes, and these increase in incidence the longer the drug is taken.
Another adverse reaction is known as ovarian hyperstimulation syndrome (OHSS) in which the ovaries enlarge, or there could be gastrointestinal problems and occasionally hypotension.
Other reactions can include breast pains, headache and unusual uterine bleeding. Later trials have shown it can also cause acne, migraines, heart problems and chest pains, liver problems, endometriosis and tinnitus.
The drug, however, is effective and can help pregnancy in 30 per cent of previously infertile women but with the very real possibility of twins or triplets or, in a few cases, quintuplets!