Fertility drugs can increase the chances of birth defects such as spina bifida by nearly six times, one report has suggested. Another says the risks are doubled, while a third has concluded there is no risk at all.

A new study from Boston University School of Public Health has tried and failed to produce a definitive answer to these concerns, which were first raised in the 1970s.

The best hope it offers women on fertility drugs is that the chances of

defects seem less with the drug clomiphene, at 0.8 times greater risk, than stronger fertility drugs.

Otherwise, it was unable to rule out the risks of a significant increase in neural tube defects, or NTD, when using the other drugs because of insufficient data.

Nonetheless, the research team, led by Dr Martha Werler, felt that risks at worse doubled, and so presumably has discounted the 1990 findings of A Milunksky et al which said risks could be increased by up to 5.8 times (Teratology, 1990; 42: 467).

The new conclusions were based on interviews with 1,034 mothers who had given birth to children with NTD defects, mainly spina bifida, and 4,081 mothers of children with other major congenital defects.

Three per cent of mothers of children with NTD defects had taken fertility drugs, against 2.8 per cent of mothers whose children had all the other congenital defects combined. The drugs included clomiphene, follicle-stimulating and luteinizing hormones (FSH+LH), human chorionic gonadotropin (HCG) and bromocriptine (The Lancet, 13 August 1994).

l A woman on IVF (in-vitro fertilization) treatment has developed breast cancer, doctors at McGill University in Quebec, Canada, have reported.

The woman, aged 36, comes from a family with a history of cancer, although the case is in line with research earlier this year which concluded that 16 of 950 patients undergoing IVF went on to develop breast cancer before they were 48.

Dr Laura Arbour at the McGill University, writing in The Lancet (27 August, 1994), wonders if the hormonal stimulation of IVF treatment might quicken the progression of cancer in those hereditarily inclined to the disease.