Good results from a study of Seasonale Lo (0.02 mg ethinyl estradiol/0.1 mg levonorgestrel), the low dose version of Seasonale (0.03 mg mg ethinyl estradiol/0.15 mg levonorgestrel):
WASHINGTON - Seasonale Lo, the 91-day extended-regimen low-dose oral contraceptive, was effective and well tolerated compared with a 28-day low-dose oral contraceptive, after both 1 year and 3 years of use.
After 1 year, the overall cumulative failure rate of Seasonale Lo was 2.23% among 463 patients, compared with a 2.83% failure rate among 231 patients who took a traditional 28-day oral contraceptive (Levlite).
Compliance rates were high--98.1% in the Seasonale Lo group and 96.5% in the Levlite group. Among compliant patients, the Seasonale Lo failure rate was only 0.65%, compared with 4.14% among compliant Levlite patients. Although more Seasonale patients reported unscheduled bleeding days than the Levlite patients (6.1% vs. 3.3%), the number of scheduled bleeding or spotting days per cycle was approximately the same in both groups.
Breakthrough bleeding episodes were reported more frequently by the Seasonale Lo group than the Levlite group (13.8% vs. 1.3%), but the incidence of other adverse events was similar between the two groups. For example, headaches, the most common adverse event, were reported by 22% of the Seasonale Lo group and 21% of the Levlite group.