Birth control pill FAQ: Benefits, risks and choices

Get the facts about common concerns and questions about birth control pills. By Mayo Clinic Staff

If you use the birth control pill — that is, an oral contraceptive — you're probably happy with its convenience and reliability. Still, you may have many questions about the potential effects of the birth control pill on your overall health.

Can you use birth control pills to delay or eliminate your period?

Yes, birth control pills can be used to reduce or eliminate monthly bleeding. When birth control pills were first available, they were packaged as 21 days of active hormonal pills and seven days of placebo pills. During the week women took the placebo pills, they would have bleeding similar to a regular menstrual period.

Today women have many more options — from regimens with 24 days of active pills and four days of placebo pills to regimens that are all active pills. The first extended-cycle pill regimens introduced provide active hormone pills every day for three months, then one week of placebo pills or low-dose estrogen pills. Newer extended-cycle regimens are designed to be taken continuously for one year and suppress all menstrual bleeding.

Continuous or extended-cycle regimens have several potential benefits. They prevent hormonal fluctuations that are responsible for bleeding, cramping, headaches and other discomforts associated with getting your period. You also may find that you like the convenience of not having a period during important events or trips.

However, unscheduled bleeding and spotting often occur during the first few months on this type of regimen. It typically goes away with continued use, but some women continue to have unscheduled bleeding with continuous use of pills.

Do you need special pills or can you use ordinary birth control pills to prevent having a period?

There are birth control pill regimens designed to prevent bleeding for three months at a time or for as long as a year. But it's possible to prevent your period with continuous use of any birth control pill. This means skipping the placebo pills and starting right away on a new pack. Continuous use of your birth control pills works best if you're taking a monophasic pill — with the same hormone dose in the three weeks of active pills.

If you plan to have a baby, how soon after stopping the birth control pill can you conceive?

After you stop taking the pill, you may have only a two-week delay before you ovulate again. Your period would follow about four to six weeks after you take the last pill. Once ovulation resumes, you can become pregnant. If this happens during your first cycle off the pill, you may not have a period at all.

Is there an advantage to waiting a few months after stopping the pill before trying to conceive?

In the past, doctors had concerns that if you conceived immediately after stopping the pill, you had a higher risk of miscarriage. However, these concerns have proved to be largely unfounded. The hormones in birth control pills don't linger in your system.

Most women have no more than a four-week delay in menses after they stop using the pill. However, if your periods were infrequent before you started taking the pill, they will likely be that way again after you stop the pill. Some women find that it takes a couple of months before they return to regular ovulatory cycles. If you plan to wait a few months, you may want to use a backup form of birth control while your menstrual cycles get back to normal.

What happens if you stop taking the birth control pill but your period doesn't resume?

If you don't get a period for several months, you may have what's known as post-pill amenorrhea. The pill prevents your body from making hormones involved in ovulation and menstruation. When you stop taking the pill, it can take some time for your body to return to normal production of these hormones.

Typically, your period should start again within three months after you stop taking the pill. But some women, especially those who took the pill to regulate their menstrual cycles, may not have a period for many months.

If you don't have a period within three months, take a pregnancy test to make sure you're not pregnant and then see your doctor.

Will a pregnancy test be accurate if you're taking the birth control pill?

You can get accurate results from a pregnancy test while you're on the pill. Pregnancy tests work by measuring a specific pregnancy-related hormone — human chorionic gonadotropin (HCG) — in your blood or urine. The active ingredients in birth control pills don't affect how a pregnancy test measures the level of HCG in your system.

What happens if you take birth control pills while you're pregnant?

If you continued taking your birth control pill because you didn't realize you were pregnant, don't be alarmed. Despite years of this accident happening, there's very little evidence that exposure to the hormones in birth control pills causes birth defects. Once you learn that you're pregnant, stop taking the birth control pill.

Can you use several birth control pills at once for emergency contraception?

It's possible to use standard estrogen-progestin birth control pills for emergency contraception, but check with your doctor for the proper dose and timing of the pills.

There are two types of pills specifically designed to keep you from becoming pregnant if you've had unprotected vaginal intercourse. These medications are sometimes referred to as the "morning-after pill." Levonorgestrel (Plan B One-Step, Next Choice) is available over-the-counter. It's available at drugstores, as well as health clinics and Planned Parenthood. Ulipristal acetate (Ella) also is approved for emergency contraception. It's available only by prescription.

May 21, 2013 See more In-depth