Comparing Birth Control Pill Types: Combination, Minipills, and More

When Enovid -- the first birth control pill -- was introduced in 1960, it was a revolution in contraception. For the first time, women could take control of their own reproductive cycles. According to Eve Espey, MD, Enovid ushered in "a whole new world for birth control." Espey is associate professor in the department of obstetrics and gynecology at the University of New Mexico. She tells WebMD it was the first time there was any kind of hormonal contraceptive "or any alternatives to condoms."

Nearly half a century later, and despite the introduction of IUDs, patches, injections, and the female condom, the pill remains the No. 1 form of contraception. It's used by an estimated 12 million women in the U.S. and 100 million women worldwide. According to Paula Hillard, MD, "When you say 'birth control,' most women think of birth control pills." A professor of obstetrics and gynecology at the Stanford University School of Medicine, Hillard says that birth control pills are still widely popular, especially among younger women.

Today's birth control pills contain a much lower dose of estrogen than their predecessors. That means they have fewer side effects. Nevertheless, they're still highly effective.

There are two basic types of birth control pills. Combination pills combine estrogen and progestin. The "minipill" contains progesterone only. There is also an emergency contraceptive pill, which is taken after unprotected sex.

Here is an overview of each type of pill and an explanation of how it works.

Birth Control Pill Type: Combination Pills

Combination birth control pills are the type most commonly associated with the term "the pill." They contain a combination of the hormones estrogen and progestin. Progestin is a synthetic form of the hormone progesterone.

Ovulation normally occurs when a spike in estrogen levels signals the ovaries to release an egg. Combination pills prevent ovulation by adjusting hormone levels to prevent this spike. They also thicken cervical mucus to prevent sperm from reaching the egg. In addition, they change the lining of the uterus to make it more difficult for a fertilized egg to implant.

Most combination pills use the same form of estrogen -- ethinyl estradiol -- but different types of progestins. For example, Mircette uses the progestin desogestrel. Yasmin uses drospirenone.

Most combination pills come in 21- or 28-day packs. With a 21-day pack, all of the pills are active. You don't take any pills for the last seven days of the cycle. It's up to you to remember when to start the next pill pack. With a 28-day pack, you take 21 active pills followed by seven inactive placebo pills.

There are three types of combination pills: monophasic, biphasic, and triphasic.

Monophasic: All of the 21 active pills contain the same level of hormones.Brand names include:

• Alesse
• Brevicon
• Demulen
• Desogen
• Levlen
• Loestrin
• Norinyl
• Ortho-Cept
• Ortho-Cyclen
• Ortho-Novum
• Yasmin
• Yaz (contains 24 active pills and four placebo pills)