The third generation oral contraceptive controversy

Papers p 820 New evidence on myocardial infarction and the recent statement from the Medicines Commission giving a greater role to clinical judgment in choosing a contraceptive pill1 call for a reassessment of the role of third generation oral contraceptives containing desogestrel or gestodene. The shift to third generation pills in the early 1990s was largely based on claims of superior cardiovascular safety. We now have evidence on which to assess these claims A lower risk of myocardial infarction in users of third compared with users of second generation pills was found in the Transnational study, although not in the British subgroup or in women aged under 35.2 However, the results did not take account of product specific differences in screening for hypertension before women started using the pill, which had a large effect in users of second generation pills (MA Lewis, personal communication). A similar influence had previously been found in the World Health Organisation study: in women whose blood pressure had been checked, the difference between the pill generations disappeared.3 It seems that undiagnosed hypertension was more common in second generation users …