Mircette is a combination oral contraceptive that utilizes both progesterone and estrogen to prevent unwanted pregnancy. The synthetic hormones used are Desogestrel, progesterone, and ethil estradiol, an estrogen. Desogestril has lower androgen (male hormone) levels and is reported to have a greater effect in inhibiting ovulation than levonorgestrel. Ethinyl estrdiol advantage is that it is absorbed quickly and last in the body longer.Combination birth control pills work by inhibiting ovulation, thining the uterine walls and thicken the mucus on the cervical walls. Estrogen in Mircette inhibits ovulation while the progesterone effects the changes in the uterus.Combination pills are usually more effective than single ingredient (estrogen only) oral contraceptives. There are two types of combination pills: those that have non-changing doses of hormones (monophasic) or varying levels of hormones (multiphasic)Multiphasic birth control comes in two types, Biphasic and triphasic. In both the, estrogen levels remain the same but the progesterone levels vary in strength. Biphasic birth control pills change progeterone hormone levels twice during the 28 day pack and triphasic contraceptive like Ortho Tri-Cyclen, change the strength of progesterone 3 times during the 28 day pack.In all cases, the last 7 days have no hormones and are provided to maintain the habit of taking pills every day.There aren’t significant differences in the effectiveness between monophasic and multiphasic pills. Deciding on the type requires consulting a doctor and how your body reacts to the medication. It’s is possible for someone to go through a few different brands before they find the one that works best for them.