Multiphasic contraceptive regimen for oral combination drug formulation of progestin and estrogen

A method of contraception in a female, comprising:

• administering to the female daily, during a time period of between 21 and 24 successive days, an oral combination drug formulation of a progestin and an estrogen,
• wherein the oral combination drug formulation is administered in a biphasic dosing regimen comprising two phases, wherein the duration of each phase is between 4 and 16 days, wherein doses of each of the progestin and estrogen in the second phase of the regimen increase by a predefined dose increment as compared to the corresponding doses of the progestin and estrogen administered during the first phase of the regimen,
• wherein the ratio of a daily dose of progestin to a daily dose of estrogen is maintained at a constant level during the entire dosing period, wherein the progestin in the oral combination drug formulation is levonorgestrel (LNG) with the dose ranging from 100 mcg to 150 mcg,
• wherein the estrogen in the oral combination drug formulation is ethinyl estradiol (EE) with the dose ranging from 20 mcg to 30 mcg, and wherein the biphasic dosing regimen is followed by a time period of between 4 and 7 days without progestin and estrogen administration.