Oral Contraceptive Pill (Birth Control Pill) Hormonal Activity

Updated: Jul 13, 2023
  • Author: Abimbola Farinde, PharmD, PhD; more...
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Hormonal Activity of Oral Contraceptive Pills

Monophasic pills

Monophasic oral contraceptive pills contain a constant amount of estrogen and progestin in each active pill. [1]

Biphasic pills

Biphasic oral contraceptive pills deliver the same amount of estrogen each day while progestin dose is increased halfway through cycle.

Triphasic pills

Triphasic oral contraceptive pills have 3 different doses of progestin and estrogen that change approximately every 7 days.

Four-phasic pills

Four-phasic oral contraceptive pills provide 4 different doses of progestin/estrogen during a 28-day cycle.

Ninety-one-day pills

Ninety-one-day oral contraceptive pills provide a constant dose of estrogen and progestin for 84 days.

Progesterone-only pills (POPs)

Progesterone-only oral contraceptive pills provide a constant dose of progestin. Norethindrone and drospirenone require a prescription. Norgestrel (Opill) is available over-the-counter without a prescription.