Marvelon is a combined oral contraceptive, commonly known as a birth control pill. It contains two different female hormones: desogestrel (a type of progestogen) and ethinyl estradiol (a type of estrogen). The combination of these hormones serves to prevent pregnancy through several mechanisms: inhibition of ovulation & thickening of cervical mucus. Marvelon works by suppressing the release of an egg (ovulation) from the ovaries. This is a key mechanism in preventing pregnancy, as without a released egg, there is no opportunity for fertilization by sperm. Marvelon also thickens the cervical mucus, making it more difficult for sperm to penetrate the cervix and reach the uterus. This reduces the chances of fertilization. The low dose of hormones in Marvelon classifies it as a low-dose oral contraceptive. The consistent hormone levels in each tablet within a package make it a monophasic contraceptive, which means that all the tablets in the package contain the same hormones in the same doses. The typical regimen for Marvelon is a 21-day cycle. It's during this break that you might experience withdrawal bleeding, like a menstrual period.