About half of the three million women in Britain who use the combined oral contraceptive pill were advised by the Committee on Safety of Medicines last week to switch to another brand, amid controversy about the way in which the new information was released. Evidence suggesting that use of two of the newer “third generation progestogens”--gestodene and desogestrel--is associated with an increased risk of venous thromboembolism was presented to the committee two weeks ago. As a result it decided to recommend that all users of brands containing the newer progestogens--Femodene, Femodene ED, Minulet, Triadene, Tri-Minulet, Marvelon, and Mercilon--should be offered the choice of switching to another brand and that these brands should be contraindicated in women who have other risk factors for venous thromboembolism.

Presenting the committee's decision at a press conference last Thursday, its chairman, Professor Michael Rawlins, said that early results from the World Health Organisation's task force on epidemiological research in reproductive health had suggested a possible association between the newer brands of the combined pill in July. The results prompted the committee to ask …