THE EFFECT OF DESOGESTREL, GESTODENE, AND OTHER FACTORS ON SPOTTING AND BLEEDING

Spotting and bleeding are among the most common side effects associate d with oval contraceptive (OC) use and their occurrence is a prime det erminant of whether a new user will continue to use OCs. Desogestrel a nd gestodene are two new progestins that were developed in part to min imize the occurrence of these side effects. Assessing the effect of th ese progestins is difficult, however, in part be cause their effects m ay be subtle, requiring a large sample size and possibly being oversha dowed by other factors. To address these issues, we analyzed data from two comparative multicenter clinical trials that included 15,421 cycl es among 2767 women. One study compared 75 mu g gestodene + 30 mu g et hinyl estradiol (EE) with 150 mu g desogestrel + 30 pg EE, the other c ompared the same gestodene preparation with 150 mu g desogestrel + 20 mu g EE. Both studies found a higher risk of spotting or bleeding in a ll cycles among users of the desogestrel-containing preparation, with the differences ranging between 20% and 70% higher for the first study and 40% and 140% in the second. These differences were statistically significant in four of six cycles in each study and persisted after co ntrolling for consis tency and recency of OC use as well as smoking. A fter pooling the data and controlling for estrogen dose, the desogestr el-containing preparation was significantly associated with more frequ ent spotting or bleeding in five of six cycles. Smoking and consistenc y and recency of OC use were also independent predictors of spotting o r bleeding.