Are You Ready for a Birth Control Makeover?

What: A big CDC survey issued last year found that the pill is the most popular form of birth control in America (used by 28 percent of women using contraception). The most common types of pills contain two hormones: estrogen and progestin (a synthetic form of progesterone), which together prevent the ovaries from releasing eggs, thicken the cervical mucus to keep sperm from joining with an egg and thin the uterine lining so that a fertilized egg would have trouble attaching.
Failure rate*: 0.3–9%

Who: Women who are more concerned with avoiding pregnancy than getting an STD; younger women who don't have kids; women who are committed to habits like flossing.

Why:

• They help regulate periods. (By the way, women on the pill don't release an egg a month like they normally would; the "period" is actually a withdrawal bleed in response to fluctuating hormone levels.)
• Carusi says the pill can clear up acne, help with heavy periods (as well as side effects like cramping), forestall bone thinning and protect against endometrial, uterine and ovarian cancers as well as serious infection in the ovaries, fallopian tubes and uterus. The pill is sometimes prescribed to women who carry a gene for ovarian cancer, Carusi says, because ovaries that aren't ovulating are less prone to this disease (unfortunately, this doesn't mean that the pill stops the ovaries from aging).

Why not:

• They require a major commitment. The website Bedsider also offers a free reminder service where they'll send a daily text or email letting you know it's time to take your pill.
• Your gynecologist can help you find a hormone level that works for you. The problem is that this trial-and-error phase can involve estrogen-related glitches like irregular and breakthrough bleeding, a flagging sex drive (due to a decrease in the amount of testosterone released by the ovaries) and brown splotches on the face.
• Many women are concerned about gaining weight, but Carusi says this is relatively uncommon and that early studies showing a correlation between the pill and extra pounds involved college students whose gains were likely due to the "freshman 15."
• It's a myth that you need to "flush the pill out of your system" before trying to conceive. The estrogen and progestin are gone within a few days. However, it's not uncommon for a woman's natural hormone levels to take two or three months to adjust to normal, which can make it tricky to predict ovulation (and therefore, to time a pregnancy).
• It's important to be aware that all contraceptives that contain estrogen—the pill, the ring, the patch, the shot—can increase the risk of blood clots, heart attacks and strokes, and they can be dangerous for women with certain risk factors (check with your doctor). Studies have reported an even greater risk for pills containing a variation of progestin called drospirenone, including Yaz and Yasmin. The FDA is currently examining this link. "I tell patients interested in Yasmin that the blood clot risk may be doubled from about three in 10,000 to six in 10,000," says Carusi. "Many women are still comfortable with this."
• Progestin-only pills, or minipills, don't have any estrogen at all. These need to be taken at the same time each day, making them an unrealistic option for those who can't stick to a routine. They also tend to cause more spotting than combo pills.