Multicenter randomized comparative trial of two low-dose triphasic combined oral contraceptives containing desogestrel or norethindrone.

OBJECTIVE

To compare a new triphasic oral contraceptive (OC) containing desogestrel and ethinyl estradiol (DSG/EE) with triphasic norethindrone/ethinyl estradiol (NE/EE) regarding effects on clinical efficacy, cycle control, and safety indices.

METHODS

In an open-label, comparative multicenter study, 407 subjects were randomized to a triphasic preparation containing DSG/EE and 405 subjects to a triphasic preparation containing NE/EE. The women were observed during six cycles of OC use.

RESULTS

The contraceptive efficacy of the triphasic DSG/EE OC was at least comparable to that of triphasic NE/EE. No pregnancies were reported with DSG/EE, whereas there were two pregnancies with NE/EE, both user failures. Cycle control with triphasic DSG/EE was statistically superior to that with triphasic NE/EE. Acceptability was excellent with both preparations as measured by the low discontinuation rates (particularly for adverse menstrual experiences). No thromboembolic or other serious drug-related adverse experiences were reported. The incidence of other drug-related adverse experiences was generally low and decreased with time in both groups. No adverse effects were seen in terms of blood pressure, body weight, laboratory indices, cervical cytology, and breast nodularity.

CONCLUSION

Triphasic DSG/EE is an effective and safe OC with excellent acceptability and cycle control superior to that of triphasic NE/EE.