Table 5.

 Rate ratio of confirmed venous thromboembolism between different combined oral contraceptives with adjustment for length of use

Product group	Women years	No of events*	Adjusted rate ratio† (95% CI)	P value
Progestogen with 30-40 μg ethinylestradiol:
Norethisterone	27 355	8	0.76 (0.36 to 1.60)	0.47
Levonorgestrel phasic	105 970	66	1.07 (0.75 to 1.52)	0.71
Levonorgestrel combined	104 251	57	1 (reference)	—
Norgestimate	267 664	119	1.18 (0.86 to 1.62)	0.30
Desogestrel	170 249	168	2.24 (1.65 to 3.02)	<0.001
Gestodene	668 355	575	2.12 (1.61 to 2.78)	<0.001
Drospirenone	286 859	196	2.09 (1.55 to 2.82)	<0.001
Cyproterone	120 934	88	2.11 (1.51 to 2.95)	<0.001
Progestogen with 20 μg ethinylestradiol:
Desogestrel	470 982	246	1.60 (1.20 to 2.14)	0.0015
Gestodene	472 118	240	1.70 (1.27 to 2.27)	0.0004
Drospirenone	23 055	16	2.22 (1.27 to 3.89)	0.005

*Events are venous thromboembolisms.

†Adjusted for age, calendar year, level of education, and length of use.