Birth control pill FAQ: From menstruation to menopause — and everything in between

The birth control pill provides many women with a reliable means of contraception. And you couldn't agree more — at this point in your life, it's the perfect form of contraception.

Still, you have many questions about taking the pill and how it can impact your overall health. Get the answers to some frequently asked questions about birth control pills (oral contraceptives). These questions come from readers like you who want to know what Mayo Clinic specialists have to say about a variety of aspects of women's health as it relates to oral contraceptive use.

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

One of the advantages of the birth control pill is that it's quickly reversible. 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. However, although possible, this scenario isn't likely. You have only a one in five chance of becoming pregnant during your first cycle trying to conceive.

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

For the purpose of dating the pregnancy — estimating when you ovulated and your due date — it may be somewhat advantageous to have at least one normal period before conceiving.

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.

If you plan to wait a few months, 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?

When you stop using the birth control pill but 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. Most women ovulate promptly and have a period within four to six weeks. 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. If after six months you still don't have a period, 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.

Still, the birth control pill is a potent estrogen. Lessons learned from women who took diethylstilbestrol — a synthetic estrogen that was later linked with cancer — to prevent miscarriage in early pregnancy suggest that such exposure should be minimized.

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 but not recommended. Don't try taking several birth control pills in an attempt to prevent pregnancy without first consulting with your doctor. Using birth control pills in this way hasn't undergone formal testing, so it's unknown whether this is even a safe thing to do.

There is, however, a special type of contraceptive pill that's specifically designed to keep you from becoming pregnant if you've had unprotected vaginal intercourse. Emergency contraception pills contain progestin or a combination of estrogen and progestin — similar to what can be found in many birth control pill formulations but in higher concentrations. Check with your doctor, local emergency room or Planned Parenthood clinic if you're in need of emergency contraception.

If you've been taking birth control pills for many years and decide to stop, can you stop at any time or should you finish your current pill packet?

In terms of your overall health, it makes little difference when you stop taking the pill. When you finally do stop the pill, you can expect some bleeding, which may change the rhythm of your menstrual cycle. But you can stop at any time.

Can you get pregnant during the week that you take the nonactive (placebo) pills?

Taking the nonactive (placebo) pills doesn't put you at higher risk of unintended pregnancy. If you're taking your birth control pills exactly as directed, they're more than 99 percent effective at preventing pregnancy.

If, however, you've missed a dose — or several doses — of your birth control pills during a cycle, you might be at higher risk of unintended pregnancy during that cycle. To be safe, use a backup form of contraception, such as a condom.

Can you use birth control pills continuously to prevent having a period?

It's possible to prevent your period with continuous use of your birth control pills. This means skipping the placebo pills and starting right away on a new pack. Some evidence suggests an advantage to this type of pill regimen. By continuously taking the pill, you prevent hormonal fluctuations that are responsible for bleeding, cramping, headaches and other discomforts associated with getting your period. However, you're at greater risk of breakthrough bleeding — bleeding between periods.

You may find continuous use of birth control pills a convenient way to avoid having your period during an important occasion or trip. Taking birth control pills continuously is fine for about three months, but then you should plan on taking the placebo pills so that you'll have a menstrual cycle.

Do birth control pills cause weight gain?

Women often blame the birth control pill for weight gain. But studies have shown that the effect of the birth control pill on weight is small — if it exists at all.

However, the way the hormones in birth control pills act on tissues in your breasts, hips and thighs can make you feel as if you've gained weight. This is usually due to fluid retention and not increased body mass or fat. Estrogen in birth control pills directly affects fat (adipose) cells, making them larger, but not greater in number.

In very rare circumstances women may add muscle, which can add weight, when taking the pill. This is due to the slight male-sex-hormone effect that the pill may have on some women.

But no matter if pill-related weight gain is perceived or real, many women find this side effect undesirable. Taking pills with a low dose of estrogen may diminish these effects, but you may also experience a greater risk of spotting between periods.

Do birth control pills affect cholesterol levels?

Birth control pills can affect cholesterol levels. How much of an effect depends on the type of pill you're taking and what concentration of estrogen or progestin it contains.

The estrogen in birth control pills causes an increase in high-density lipoprotein (HDL) cholesterol levels (the "good" cholesterol), a decrease in low-density lipoprotein (LDL) cholesterol levels (the "bad" cholesterol) and an increase in your total cholesterol and triglyceride levels. Progestin in birth control pills has the opposite effect.

Birth control pills with a greater concentration of estrogen can have a slightly beneficial overall effect on your blood lipid levels. In general, though, the changes aren't significant and don't affect your overall health.

Do birth control pills affect blood pressure?

Birth control pills may increase blood pressure. The risk of high blood pressure in women who take birth control pills also increases with age and the duration of use. Birth control pills contain progestins, drugs that mimic the activity of the naturally occurring hormone progesterone. Progestins are responsible for high blood pressure when it occurs. Unfortunately, changing pill formulations usually doesn't alter the effect on blood pressure.

If you take birth control pills, have your blood pressure checked regularly. If you already have high blood pressure, consider an alternative form of birth control. If you do choose to take the pill, have your blood pressure closely monitored by your doctor.

If you develop high blood pressure while taking the pill, give serious thought to switching to another form of contraception.

Can antibiotics decrease the effectiveness of birth control pills?

The effects of antibiotics on birth control pills may be overstated — except in the case of one antibiotic, rifampin. Studies clearly show that rifampin decreases the effectiveness of birth control pills in preventing ovulation.

Hypothetically speaking, other antibiotics, particularly penicillin and tetracycline derivatives, could impair the effectiveness of birth control pills. However, no large studies have proved such an effect.

Researchers can't rule out the possibility that a small percentage of women may experience decreased effectiveness of birth control pills while taking an antibiotic. And if you're taking a newer, extremely low-dose oral contraceptive, you could be more susceptible to these potential effects from antibiotics. If you're concerned, consider using a barrier method of contraception for the duration of your antibiotic prescription.

Do birth control pills prevent or delay menopause?

A woman still goes through menopause even if she is taking birth control pills. But she may not know it.

Menopause occurs naturally when your ovaries stop making estrogen and progesterone. Eventually your menstrual periods stop, and you can no longer become pregnant. Signs and symptoms of decreased production of estrogen and progesterone include hot flashes, sleep disturbances and vaginal dryness.

A menopausal woman taking birth control pills continues to get enough estrogen and progestin from the pills and will not realize her ovaries are no longer making these hormones. Her periods will continue, although she can no longer get pregnant. Menstruation occurs during the placebo week of the pill regimen. And she may have no symptoms of menopause because the pill continues to deliver more than adequate amounts of estrogen and progestin.

This is important to know. Research suggests that there's a small risk associated with taking hormone therapy during menopause, and it shouldn't be used routinely. Oral contraceptives provide a much more potent dose of estrogen and progestin than does hormone therapy for menopause, and the risks are significantly higher.

If you're taking the pill and are older than age 50, consider stopping oral contraceptive use. Discuss with your doctor how you can determine whether menopause has occurred and what alternatives there are to contraception if you still need it.

Why is it OK for a woman in her 20s to take birth control pills while a woman in her 50s should think twice about hormone therapy? Aren't they the same thing?

Hormone therapy and birth control pill use aren't the same.

Hormonal activity in your body differs markedly before and after menopause. The birth control pill regulates hormones that your ovaries are already producing. Hormone therapy for menopause provides your system with the hormones that your ovaries stopped producing after menopause.

The estrogens and progestins found in birth control pills, although from the same family of hormones, contain different types and doses from the combination pills commonly used for hormone therapy (Prempro, others). Birth control pills use more potent estrogens and progestins, and they're used at higher doses.

Taking birth control pills offers many advantages during your reproductive years, the most notable being reliable family planning and reducing your risk of ovarian and endometrial cancers. The benefits tend to outweigh the risks.

However, postmenopausal hormone therapy if you're not experiencing disabling menopausal symptoms, such as hot flashes, night sweats or vaginal dryness, offers little benefit. And it introduces a slightly increased risk of heart problems, some cancers and negative effects on memory.

The complex nature of hormonal treatments — both as contraception and as a therapy for menopausal symptoms — is worthy of a discussion with your doctor about the health risks and benefits in your particular situation.

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