Effect on stroke of different progestagens in low oestrogen dose oral contraceptives. WHO Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception.

The multicentre WHO collaborative case-control study had limited power to differentiate stroke risks by progestagen component in low dose combined oral contraceptives. Given this caveat, odds ratios for ischaemic, haemorrhagic, and all strokes combined associated with use of oral contraceptives containing desogestrel or gestodene ("third generation") were found to be similar to those containing levonorgestrel in this study.