Context Oral contraceptive (OC) pills are effective, but poor compliance increases
rates of pregnancy during treatment.
Objective To compare the contraceptive efficacy, cycle control, compliance, and
safety of a transdermal contraceptive patch and an OC.
Design Randomized, open-label, parallel-group trial conducted October 1997
to June 1999.
Setting Forty-five clinics in the United States and Canada.
Participants A total of 1417 healthy adult women of child-bearing potential.
Interventions Participants were randomly assigned to receive a transdermal contraceptive
patch (n = 812) vs an OC (n = 605) for 6 or 13 cycles. Patch treatment consisted
of application of 3 consecutive 7-day patches followed by 1 patch-free week.
Main Outcome Measures Overall and method-failure Pearl Indexes (number of pregnancies/100
person-years of use) and life-table estimates of the probability of pregnancy
were calculated. Cycle control, compliance, patch adhesion, and adverse events
were also assessed.
Results Overall and method-failure Pearl Indexes were numerically lower with
the patch (1.24 and 0.99, respectively) vs the OC (2.18 and 1.25, respectively);
this difference was not statistically significant (P
= .57 and .80, respectively). The incidence of breakthrough bleeding and/or
spotting was significantly higher only in the first 2 cycles in the patch
group, but the incidence of breakthrough bleeding alone was comparable between
treatments in all cycles. The mean proportion of participants' cycles with
perfect compliance was 88.2% (811 total participants, 5141 total cycles) with
the patch and 77.7% (605 total participants, 4134 total cycles) with the OC
(P < .001). Only 1.8% (300/16 673) of patches
completely detached. Both treatments were similarly well tolerated; however,
application site reactions, breast discomfort, and dysmenorrhea were significantly
more common in the patch group.
Conclusion The contraceptive patch is comparable to a combination OC in contraceptive
efficacy and cycle control. Compliance was better with the weekly contraceptive
patch than with the OC.