Pezzini 2007.

Methods	Case‐control study
Participants	108 cases/216 controls Aged < 45 years
Interventions	Combined oral contraception: current and none use
Outcomes	Ischemic stroke Events: current use 43/31, none use 65/185
Notes	Italy
Risk of bias
Bias	Authors' judgement	Support for judgement
Exposure ascertainment	High risk	COC use not objectively confirmed.
Outcome assessment	Low risk	Ischemic stroke objectively confirmed.
Follow‐up	Unclear risk	Not applicable as this was a case‐control study.
Source population	High risk	Controls from a different source population to the cases.