Background: A recent study found that NuvaRing (a vaginal contraceptive ring containing 15 mu g ethinyl estradiol and 120 mu g etonogestrel) has 2.5 times increased relative risk of thrombotic stroke compared to nonuse. Objective: We studied a case series of 19 such patients as well as prior published case reports to clarify clinical, radiological, and prognostic features. Methods: Medical records and imaging for 18 cases were initially systematically reviewed for consultation in a class action lawsuit. One case was seen personally outside of litigation. All 19 cases were entered into a database detailing clinical, radiological, and prognostic features as well as other potential risk factors. A literature search identified 8 additional cases. Results: Average age at stroke was 31.7 +/- 9.8 years; average duration of NuvaRing use prior to stroke was 11.2 months. Arterial stroke occurred in 10 of 19 (52%); 1 of 10 (10%) was hemorrhagic. Venous sinus thrombosis was present in 11 of 19 (58%) on initial imaging; 6 of 11 (54%) were hemorrhagic. The most common presenting symptom was headache (7 of 19 [37%]) and motor weakness (7 of 19 [37%]). A hypercoagulable condition was present in 3 of 19 (16%); 3 of 19 (16%) had history of hypercoagulable disease in a first-degree relative. Mortality was .5%; 8 of 19 (42%) fully recovered and 3 of 19 (15%) were discharged to rehabilitation. Conclusions: In this largest case series of NuvaRing-associated stroke to date, approximately half of the strokes are venous and half are arterial. Stroke typically occurred within the first year of use, and as soon as 2 weeks after NuvaRing initiation.