Bookmarkers beware: Bookmarks to pages other than the home page may not work after we change servers in April Editor's Choice | This Week in BMJ | Press releases BMJ No 7126 Volume 316 News Saturday 17 January 1998 Warning about contraceptive device given The Department of Health has advised GPs that the contraceptive device Persona may be unsuitable for couples who would find an unplanned pregnancy completely unacceptable. Persona tests hormone levels in urine to enable women to avoid unprotected intercourse during the fertile phase of the menstrual cycle. The warning came after the Medical Devices Agency carried out an investigation into Persona in response to complaints about its reliability from users, GPs, and trading standards officers. The manufacturers of the device, Unipath, claim that a clinical trial conducted before the device was marketed showed that it is 94% reliable, which means that if 100 women use Persona for one year six would be expected to become pregnant as a result of the device incorrectly identifying the fertile phase. The Medical Devices Agency stated that it was unable to substantiate the reliability because Unipath declined to provide data from the trial. However, John Newton, professor of obstetrics and gynaecology at the University of Birmingham and one of the independent experts who took part in the investigation, said: "The clinical data are available - the Medical Devices Agency sent them to me. I am very happy with the results, which were collected carefully following good clinical guidelines. The device is 94% reliable." Last week's letter from the agency to GPs suggested that Persona is a useful addition to the range of contraceptive choice. But it warned: "Persona is basically a test-based form of the rhythm method of contraception. However, due to its technological basis, expectation of Persona may be higher than for other forms of contraception." The agency said: "Users of Persona should be aware that 94% reliability as defined may also be expressed as a risk of 1 in 17 users becoming pregnant per year of use." The agency also pointed out that the device is not suitable for women whose menstrual cycle lengths do not fall within the range of 23-35 days; for those using the contraceptive pill, hormone replacement therapy, or infertility treatment; or for those who have recently given birth or are breast feeding. Dr Keith May, vice president for research and development with Unipath, confirmed that its clinical trial carried out before the launch had included women from a wide range of ages, educational background, and social status. "We have tried right from the start to give all of the information necessary for consumers to make informed decisions, and we continue to work to improve our communication with users." Susan Mayor London Home | Current issue | Past issues | Classified ads | Career Focus | Feedback Collections | About this site | About the BMJ | BMA | Medline