New birth control may be more reliable

Two new hormonal birth control methods may offer American women better-than-ever efficacy at preventing pregnancy, and a chance to banish monthly menstrual periods. But the methods carry a side effect that women might not want: a big chance of unpredictable spotting.

A pill called Lybrel, approved by the U.S. Food and Drug Administration in May, and Implanon, an implant for the arm that was green-lighted this month, are the latest in a string of contraceptive advances that have included hormonal rings and patches, intrauterine devices and female condoms.

"The newest couple of concepts in birth control involve sort of playing with hormones to do something different than we used to do," says Dr. Ashlyn Savage, an assistant professor of obstetrics and gynecology at the Medical University of South Carolina.

The methods are shaking up the clockworklike, 28-day cycles that women on the pill are used to. Lybrel is a birth control pill that's meant to be taken continuously, without a break each month for a week of placebo pills. That means no periods. The "period" that women on the pill typically have is actually withdrawal bleeding from taking a break in pills containing active ingredients, but doctors say the number of days in each cycle on the pill are arbitrary, created only by the number of pills placed in each pack.

"Back in the '60s, when people developed hormonal methods, they were attempting to reproduce a woman's normal menstrual function," says Dr. Victor Weinstein, a obstetrician/gynecologist with Ashley River OB/GYN. "They thought that was probably important, but it's really not."

Since combination oral contraceptives — those that contain two hormones, estrogen and progesterone — keep the uterine lining thin, he says, there's no biological reason to shed it on a monthly basis. Some women, however, prefer to have a period to be sure they aren't pregnant.

And the new drug isn't without its controversy: Lybrel's launch has irked feminist groups who've accused its maker of turning menstruation into a disease that needs to be "treated."

But while the brands Lybrel and Seasonale, a pill that went on the market in 2003 and causes just four periods a year, may be new, the science behind them isn't. Doctors long have treated women with heavy, painful periods by prescribing active birth control pills continuously, without the typical weeklong break for placebo pills each month.

In fact, Weinstein notes that women who wish to take the pill continuously would likely save money by choosing to take a generic pill continuously rather than using Lybrel, which doesn't yet have a generic equivalent and could cost about $480 for a year's supply.

Savage expects that women who have menstrual migraines, those spurred by hormonal changes during each period, or whose heavy, crampy periods haven't been helped by traditional pills will be most apt to choose the drug. Other women pick the new regimens because of what Savage calls their "cosmetic" benefits: shorter, lighter periods, and in the case of Lybrel, none at all.

"I see college-aged girls who are like, 'Heck yeah, three periods a year!' " she says.

Doctors also suspect that the newest pill formulations could outperform regular birth control pills when it comes to preventing pregnancy.

With perfect use, all birth control pill regimens are least 98 percent effective, meaning less than two women of every 100 would become pregnant during a year using the method. Taking the pill each day, at around the same time, is key to their efficacy. But since most women refill their pill prescription each month, procrastination may result in missing the first day or two of a new pack. Doctors think those missed days may account for why the drugs' actual failure rate is closer to 8 percent.

The first pills of each monthly pack are the most important, Savage says, because during that placebo week, the body can begin the process of recruiting follicles to mature into an egg to be released by an ovary later in the month. Although the issue hasn't been studied extensively yet, she believes pills such as Lybrel and Seasonale, which are packaged in larger amounts, thus decreasing the number of trips to the pharmacy, also may cut the number of accidental pregnancies among users.

One study on the drug showed that none of the 323 women who took Lybrel became pregnant, while three of the 318 women who took a traditional 21-day oral contraceptive did.

"With these extended regimens, you have less first days of the month, and you're giving yourself less of an opportunity to have 'escape ovulation' because you've taken enough time away from active pills," Savage says.

Many birth control users already are mothers, or hope to have children in the future, and some women worry that long-term use of hormonal methods could hamper their ability to get pregnant when they want to. Doctors point to research that shows otherwise.

A study run by Lybrel's maker, Wyeth, showed that 99 percent of 187 participants either got their period or became pregnant within 90 days after stopping the drug. In studies where women who used Implanon, a single rod-shaped implant that is placed between the bicep and tricep muscles in the upper arm, participants returned to their normal cycle patterns almost immediately.

The implant, which suppresses ovulation using only the hormone progesterone, is good for three years. Unlike Norplant, a set of matchstick-size implants that were approved by the FDA in the early 1990s and later pulled from the market, doctors say Implanon is easy to remove and can't get "lost" or encapsulated under the skin.

Since the implant doesn't contain estrogen, which has been linked to blood clots among certain patient groups, doctors say it's more apt to be safe for use in women who are older than 40 or who smoke.

While users of both methods likely won't get a "normal" monthly period, they may experience spotting throughout the month. Among Lybrel users, the irregular bleeding may taper off over time, but those with Implanon may find that the side effect persists. Women may find they bleed less over, say, a three-month time frame, but that they have no idea when it will come or go, Weinstein says. The pattern may change from one month to the next, too.

"Unfortunately, the data looks like the unpredictable bleeding never really gets all that better," Savage says.

For now, doctors say they're most likely to recommend it to women who are prepared to deal with that side effect, or those who need fail-safe birth control, such as those with chronic illnesses whose health would be endangered by pregnancy.

Medicaid plans to pay for its patients to get the implant if they're interested, but Weinstein notes that many South Carolina insurers don't cover the costs of implantable birth control. Out-of-pocket costs for Implanon are expected to be about $500, less expensive than three years of most birth control pills.

Reach Holly Auer at 937-5560 or hauer@postandcourier.com, or visit The Daily Meds blog at www.postscripts.typepad.com/the_daily_meds.