Background: It has been suggested that the risk for cerebral venous sinus thrombosis (CVST) may be greater among users of the contraceptive patch than among users of oral contraceptives (OCs).
Methods: From the PharMetrics database, we identified women aged 15-44 years who filled at least one prescription for either the contraceptive patch or desogestrel-containing, norgestimate-containing or levonorgestrel-containing OCs to assess the risk of CVST. The person-time of current exposure to each study drug, as well as the incidence rates (IRs) and incidence rate ratios (IRRs) of CVST, was calculated.
Results: We identified over 1 million users of the four study drugs. There were five cases of CVST among current users of desogestrel, seven cases among current users of norgestimate, two cases among current users of levonorgestrel and none among current users of the contraceptive patch. The IRs per 100,000 woman-years were 2.7 [95% confidence interval (95% CI)=0.9-6.3], 1.6 (95% CI=0.7-3.3), 0.7 (95% CI=0.1-2.4) and 0.0 (95% CI=0.0-4.8), respectively, in users of desogestrel, norgestimate, levonorgestrel and the contraceptive patch. There were two women who had CVST while not currently taking a hormonal contraceptive (IR=0.4 per 100,000 woman-years; 95% CI=0.1-1.3). The IRRs were 4.0 (95% CI=0.7-42.4) for desogestrel-containing versus levonorgestrel-containing OCs, and 2.4 (95% CI=0.5-24.0) for norgestimate-containing versus levonorgestrel-containing OCs. The IRR for the patch could not be calculated.
Conclusions: There is no evidence of an increased risk of CVST in users of the contraceptive patch compared to users of levonorgestrel-containing OCs.