Table 1.

Incidence of venous thromboembolism and use of combined oral contraceptives before and after October 1995

	Jan 1993-Oct 1995 (period 1)	Nov 1995-Dec 1998 (period 2)
Observed population aged 15-49 (1000s woman years)	1516	1677
Exposed population aged 15-49 (1000s woman years)	260.9	258.8
No of cases of venous thromboembolism	90	97
Oral contraceptive years per 100 woman years	17.2	15.4
% of oral contraceptives containing gestodene or desogestrel	53.4	14.0
No of venous thromboembolisms/100 000 exposed woman years*	34.5	37.5 (35.9†)

^*Exposed to combined oral contraceptives. 

^†Rate standardised to age distribution of period 1.