ORTHO EVRA (norelgestromin and ethinyl estradiol) is a newly developed transdermal contraceptive system (a "patch") available in the U.S. since April 2002. The study uses data from the Ingenix Research Database to assess the risk of venous thromboembolism [blood clots; pulmonary embolism (PE) and deep vein thrombosis (DVT)], acute heart attack, and stroke among women using the transdermal contraceptive system, ORTHO EVRA (norelgestromin and ethinyl estradiol), compared with women using norgestimate-containing oral contraceptives with 35 mcg ethinyl estradiol, during the period 4/1/2002 to 12/31/2004. The Ingenix Research Database is a United States health care claims database derived from comprehensive databases of UnitedHealth care. After obtaining IRB approval and a waiver of authorization, requests will be made for medical records for all patients whose claims sequence is possibly consistent with the occurrence of VTE (blood clots), AMI (heart attack), or stroke. A nested case control study will be conducted to estimate the relative risks of VTE (blood clots), AMI (heart attack, and stroke with special attention to duration of use of the last course of treatment before event onset. An additional case-control study will evaluate the effects of the risk estimates of missed cases in women on a professional sample of the contraceptive who do not have claims evidence of hormonal contraception and are non-pregnant childbearing aged.

Transdermal patch containing 6 mg norelgestromin and 0.75 mg ethinyl estradiol worn for 1 week and replaced for 3 consecutive weeks; 4th week is patch-free. Norgestimate-containing oral contraceptives with 35 mcg ethinyl estradiol taken 21 consecutive days, then no pill or a drug-free pill 7 days.