Malcolm Potts, Professor of Population Studies and International Health at the University of California, argues in the book HIV Infection in Women, now published in this country, that inter-uterine devices (IUDs) can make women more vulnerable to infection with HIV during sexual intercourse without a condom, and may mean they are more likely to pass the virus on.
Dr Potts stresses in the book that the case against IUDs is far from proved. But his claims have the backing of other researchers and have prompted calls for more research into the safety of female contraceptive methods.
IUDs cause inflammation in the wall of the uterus which greatly increases levels of the type of white blood cells which are the target of HIV in the uterus and upper genital area.
That could make an HIV- positive woman more infectious and put a healthy woman more at risk, by providing more 'target' white blood cells for the virus to attack, he says.
Second, IUDs can make menstruation longer and heavier. An infected woman not only poses the greatest risk to her partner when she is bleeding, but also, because the uterine wall is left without a protective covering, she may be more likely to pick up an infection, including the HIV virus, from an infected man. Dr Potts argues that the inflammation caused by the insertion of IUDs into the uterine wall can nurture infections.
His claims follow two studies linking IUDs with HIV- transmission. The first looked at 368 women in Italy who were steady partners of HIV-infected men. Women with IUDs were found to have a three-fold risk of picking up the HIV virus - an increase greater than that associated with anal sex. The study was published in the journal Archives of Internal Medicine in December 1991.
The second study covered more than 2,000 women attending a family planning clinic in Dar-es-Salaam, Tanzania. Presented at the international Aids Conference in Amsterdam in 1992, the study also found a three-fold increased risk of HIV in women with IUDs, after adjusting for age, marital status, number of sex partners, condom use, and other risk factors.
Margaret Johnson, HIV and Aids consultant at the Royal Free Hospital, London, and editor of a new book on the subject, said she would 'echo exactly' what Dr Potts was saying.
'We don't have enough information to say that IUDs are safe,' Ms Johnson said. 'There are theoretical arguments against them and we need the data to back them up.'
David Hicks, a consultant genito-urinary physician and a specialist in sexually transmitted diseases at the Royal Hallamshire Hospital in Sheffield, said IUDs were an 'excellent contraceptive' for women at low risk of catching HIV.
Specialists say that copper-releasing IUDs - introduced over the last five years and now used by nine out of 10 women with such devices - are smaller, cause less inflamation, and produce fewer new white blood cells than the older plastic models.
But they have not eliminated inflammation altogether, according to Diana Moran, deputy medical director of the Margaret Pyke Family Planning Centre, who said inflammation could be enhanced by the addition of copper to the IUD.
Specialists also stress the need for more research. Susan Crane, executive director of Family Health International, an Aids research lobby group, said that few studies were being conducted on the simple mechanics of HIV-transmission, and whether contraceptives made any difference.
'Researchers seem to think that the mechanics of HIV- transmission, and the effect on HIV of contraceptive devices, is too boring to bother with,' she said.
HIV Infection in Women. Johnson and Johnston (Churchill Livingstone pounds 60).Reuse content