Yasmin, a low-dose birth control pill, was approved by the U.S. Food and Drug Administration (FDA) in May 2001 and is available in the United States. It is 99 percent effective in preventing pregnancy when used correctly, and works in the same way as other combination birth control pills. Each pill pack consists of 21 pills that contain the same amount of estrogen and progestin, to be taken one per day for three weeks, followed by seven placebo pills that are taken throughout the week, in order for a woman to get her period. A newer formulation of Yasmin, called Yaz, has 24 active pills and four placebo pills. The Yaz (24-day) formulation is FDA approved as a method of birth control, as well as a treatment for premenstrual dysphoric disorder (PMDD) and acne.

As the only birth control pill to contain the synthetic progestin known as drospirenone, Yasmin is an alternative for women who experience adverse effects from other oral contraceptives. Drospirenone has antimineralocorticoid activity that influences the regulation of water retention and electrolyte balance in the body, as well as antiandrogenic (anti-male hormone) properties. It may even be effective in treating premenstrual dysphoric disorder (PMDD), a severe form of premenstrual syndrome (PMS).

Birth control pills, or oral contraceptives (OCs), are commonly referred to as "the Pill." Among reversible birth control methods, the Pill is considered one of the most effective. A woman naturally produces two different hormones that regulate her ovulation and menstruation: estrogen and progesterone. Birth control pills contain synthetic hormones that are similar to these naturally occurring hormones. Combination pills contain an estrogen and a progestin and work in two ways:

• The body is "tricked" into thinking it is pregnant. This prevents the release of an egg, or ovulation. Without an egg to be fertilized, a woman cannot become pregnant.
• The cervical mucus is thickened, making it difficult for sperm to travel toward the egg and fertilize it in case an egg is released.