- What are the Different Birth Control Medications?
- Drug and Food Interactions and Side Effects of Birth Control Medications
- Hormone-Containing Contraceptives
- Monophasic Pills
- Biphasic Pills
- Triphasic Pills
- Ninety-One-Day Birth Control Pills
- Topical Contraceptive Patch
- Long-Acting, Injectable, Progesterone-Only Contraceptives
- Progesterone-Only Pills
- Vaginal Ring
What are the Different Birth Control Medications?
Birth control (contraceptive) medications contain hormones (estrogen and progesterone, or progesterone alone). The medications are available in various forms, such as pills, injections (into a muscle), topical (skin) patches, and slow-release systems (vaginal rings, skin implants, and contraceptive-infused intrauterine devices [Mirena]).
Choosing which estrogen and progesterone dose, type, and administration method is highly patient specific, meaning that the choice greatly depends on factors unique to an individual. General goals are to choose a product that provides good menstrual cycle control with the fewest adverse (side) effects and to use the lowest hormone dose possible that will consistently prevent pregnancy. After beginning birth control medications, it may be necessary to adjust the dose or to choose a different product.
The estrogens and progesterones contained in birth control medications available in the United States include the following:
- Ethinyl estradiol
- Norethindrone acetate
- Ethynodiol diacetate
- How birth control medications work: Hormonal birth control medications prevent pregnancy through the following ways:
- By blocking ovulation (release of an egg from the ovaries), thus preventing pregnancy
- By altering mucus in the cervix, which makes it hard for sperm to travel up the uterus.
- By changing the endometrium (lining of the uterus) so that it cannot support a fertilized egg
- By altering the fallopian tubes (the tubes through which eggs move from the ovaries to the uterus) so that they cannot effectively move eggs downward toward the uterus
- Who should not use these medications: Women with the following conditions should not use estrogen-containing birth control medications:
- Allergy to any component of the product
- History of blood clot disorders
- History of stroke or heart attack
- Heart valve disease with complications
- Severe uncontrolled hypertension
- Diabetes that has caused blood vessel disease
- Poorly controlled diabetes
- Severe headaches (for example, migraines)
- Recent major surgery with prolonged bed rest
- Breast cancer
- Active liver cancer (or liver disease)
- Uterine cancer or other known or suspected estrogen-dependent cancers
- Unexplained abnormal bleeding from the uterus
- Jaundice during pregnancy or jaundice with prior hormonal contraceptive use
- Known or suspected pregnancy.
Drug and Food Interactions and Side Effects of Birth Control Medications
Drug or Food Interactions
Contraceptive effectiveness may be reduced by antibiotics, antifungals, anticonvulsants, anti-HIV drugs, St. John’s Wort, and other drugs that speed the body’s breakdown and use of contraceptive hormones, which could result in unintended pregnancy or breakthrough bleeding. Examples of such drugs include barbiturates (amobarbital [Amytal], phenobarbital [Barbita, Luminal]), griseofulvin (Grifulvin V, Gris-PEG), rifampin (Rifadin, Rimactane), phenylbutazone (Butazolidin), phenytoin (Dilantin), carbamazepine (Carbatrol, Tegretol), felbamate (Felbatol), oxcarbazepine (Trileptal), topiramate (Topamax), and, possibly, ampicillin (Marcillin, Omnipen).
Birth control may cause a change in vision, necessitating a change in eyeglass prescription, or an inability to wear contact lens. Birth control pills do not provide protection from sexually transmitted diseases (STDs). The pills ideally should be taken daily and consistently at the same time every day. If a woman stops taking birth control pills, it may take several months for her normal ovulatory cycle to return. Once the pills are stopped, a woman can become pregnant even if her menstrual cycle has not returned to normal. The following general side effects apply to all the hormonal birth control medications, regardless of how they are taken (for example, pills, topical patch, injection): nausea, breast tenderness, fluid retention, weight gain, acne, breakthrough bleeding, missed periods, headaches, depression, anxiety, other mood changes, and decreased sexual desire. Additionally, the following more serious complications may occur:
- Thromboembolism (blood clots): Women who use estrogen-containing birth control pills are at a 3- to 6-fold increased risk of developing blood clots. Blood clots may lead to deep vein thrombosis, pulmonary embolism, or stroke. Additional causes of blood clots include advanced age, obesity, family history, recent surgery, and pregnancy. Low-dose (less than 50 mcg of ethinyl estradiol) oral contraceptives pose less risk than older, higher-dose formulations. Cigarette smoking increases the risk of blood clots in women using combination contraceptives, particularly for women older than 35 and those who smoke more than 15 cigarettes per day.
- Breast cancer: The association of birth control pill use and breast cancer in young women is controversial. The Collaborative Group on Hormonal Factors in Breast Cancer performed the most comprehensive study in 1996. The results demonstrated that current pill users and those who had used birth control pills within the past 1-4 years had a slightly increased risk of breast cancer. Although these observations support the possibility of a marginally elevated risk, the group noted that pill users had more breast examinations and breast imaging studies than those found in non-users. Thus, although the consensus states that birth control pills can lead to breast cancer, the risk is small, and the resulting tumors spread less aggressively than usual. Many doctors currently believe that birth control pill use might interact with another risk factor to stimulate breast cancer.
- Cervical cancer: The relationship between birth control pill use and cervical cancer is also quite controversial. The risk is not related to the contraceptive agent itself but to how it leaves a woman unprotected from STDs. Early sexual intercourse, numerous lifetime sexual partners, and exposure to human papillomavirus are all important risk factors. Most authorities now believe that, if birth control pills increase the risk of cervical cancer at all, the risk is minimal.
- Benign liver tumors: Hormones are metabolized by the liver. A small increase in the frequency of benign liver tumors may exist, particularly after 4-8 years of birth control pill use.
- Diabetes: Progesterone and high estrogen doses may alter blood glucose (sugar) levels in diabetic women.
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Combination contraceptives, that is, contraceptive medications containing both estrogen and progesterone, are the most effective means for contraception with the exception of surgical sterilization. Several types of combination birth control pills exist, including monophasic pills, biphasic pills, triphasic pills, and 91-day-cycle pills.
- Use: Starting at the beginning of the pill pack, take 1 each day at approximately the same time every day to increase protection from pregnancy. Keep the pills in the original container to ensure they are being taken correctly (the container labels each pill with a day of the week to make it easy to follow along with the calendar).
- When to begin: The following regimens may be used when first starting on birth control pills:
- Taking 1 pill each day, starting on the fifth day after the onset of menses (menstruation, menstrual period) and continuing for 21 or 28 days (see following instructions for 21- vs 28-day containers)
- Beginning pills on the first day of the menstrual period
- Beginning on the first Sunday after the menstrual period starts
- Twenty-one-day birth control pill container: Take 1 pill daily for 21 days, stop for 7 days (a period should start during this time), then resume taking the pills with a new container of pills.
- Twenty-eight-day birth control pill container: Start with the first pill in the container, and swallow 1 daily for 28 days. Do not stop taking the pills. The last 7 pills do not contain hormones and are usually a different color than the other 21 pills in the container. These last 7 pills are placebos (some contain an iron supplement) intended to help keep women on schedule taking your pills. A period will usually begin while taking the last 7 placebos.
- Ninety-one-day birth control pill: One pill is taken daily for 12 weeks (84 days), followed by 1 week (7 days) of inactive pills. A menstrual period occurs during the week of inactive pills, so women on this regimen have a period only once every 3 months.
- If pills are missed: Missed doses should be taken as soon as possible. The next pill is taken at the regular time. If more than 1 pill is missed, begin taking the pills as soon as possible, but also use an additional form of birth control for the remainder of the cycle. Women who miss more than 1 pill per cycle are at greater risk of becoming pregnant.
- Missed period: Pregnancy should be ruled out as a possible cause of missed periods while on birth control pills. Birth control pills should be discontinued if pregnancy is confirmed.
- When to seek immediate medical attention: Seek emergency medical care if any of the following symptoms occur: abdominal pain, chest pain, headaches (severe), eye changes (blurred vision), or severe thigh or calf pain. These symptoms are easy to remember by learning the mnemonic device ACHES.
Monophasic pills have a constant dose of both estrogen and progestin in each of the hormonally active pills throughout the entire cycle (21 days of ingesting active pills). Several of the brands listed above may be available in several strengths of estrogen or progesterone, from which doctors choose according to a woman’s individual needs.
Jenest, Mircette, Necon 10/11, Nelova 10/11, Ortho-Novum 10/11
Biphasic pills typically contain 2 different progesterone doses. The progesterone dose is increased about halfway through the cycle.
Triphasic pills gradually increase the dose of estrogen during the cycle (some pills also increase the progesterone dose). Three different increasing pill doses are contained in each cycle.
Ninety-One-Day Birth Control Pills
Levonorgestrel/ethinyl estradiol (Seasonale)
These pills are monophasic birth control pills that have been approved for use on a daily basis for 84 days without interruption. Users have fewer scheduled menstrual cycles (only 1 period every 3 months). Data from clinical trials show that many women, especially in the first few cycles of use, have more unplanned bleeding and spotting between the expected menstrual periods than women taking conventional combination birth control pills.
Topical Contraceptive Patch
Norelgestromin/ethinyl estradiol (Ortho Evra)
The topical patch may be applied to clean, dry skin on the shoulders, upper arms, buttocks, or abdomen. It should not be applied to red or inflamed areas of the skin or in areas where tight clothing may rub. The patch may be less effective in women weighing more than 198 pounds (90 kg).
- Use: A new patch is applied on the same day of the week, each week for 3 weeks in a row. The first patch is applied either on the first day of the menstrual period or on the Sunday following the onset of menses. On the fourth week, no patch is applied. Menstruation should begin during this time. This 4-week period is considered 1 cycle. Another 4-week cycle is started by applying a new patch following the 7-day patch-free period.
- Side effects: Side effects are similar to other birth control agents containing both estrogen and progesterone. Effects include menstrual irregularities, weight gain, and mood changes. Other specific side effects include a skin reaction at the site of application and problems with contact use.
Long-Acting, Injectable, Progesterone-Only Contraceptives
- Use: Administration of the injection requires a visit to a doctor’s office. The first injection is given within 5 days following the onset of menstruation. After that, an injection is needed every 11-13 weeks. Unlike pills, the injection works right away; therefore, additional contraception is not needed when beginning the shots.
- Side effects: Since progesterone is the only hormonal ingredient, estrogen-related side effects are avoided. A side effect unique to this method of birth control is that most women eventually stop having their periods. Because the drug is maintained in the body for a long time (at least 3 months), periods may take longer to resume after stopping injections, compared with birth control pills. Depo-Provera may last in the body for several months in women who have used it on a long-term basis and can actually delay the return to fertility after stopping the drug. Approximately 70% of former users desiring pregnancy conceive within 12 months, and 90% of former users conceive within 24 months. Other side effects include weight gain and depression.
Progesterone-only pills (POPs), also known as mini-pills, are not used widely in the United States. Less than 1% of users of oral contraceptives use them as their only method of birth control. Those who use them include women who are breastfeeding and women who cannot take estrogen.
- Use: POPs are ingested once daily, every day. POPs may be started on any day, and there are no pill-free days or different-colored pills to track. Since progesterone is the only hormonal ingredient, estrogen-related side effects are avoided. However, since POPs do not include estrogen, they have a higher failure rate. Users must take this pill at the same time daily for greatest effectiveness.
Etonogestrel/ethinyl estradiol (NuvaRing)
- Use: The ring is self-inserted into the vagina. Exact positioning is not required for it to be effective. The vaginal ring must be inserted within 5 days of the onset of the menstrual period, even if bleeding is still occurring. During the first cycle, an additional method of contraception, such as male condoms or spermicide, is recommended until after the first 7 days of continuous ring use. The ring remains in place continuously for 3 weeks. The ring is then removed for 1 week. Menstruation should begin during this week. The next ring is inserted 1 week after the last ring was removed.
- Side effects: Because the hormones in the ring are absorbed directly into the body, some side effects of oral contraceptives, such as nausea, can be minimized. However, other side effects are similar to those of other birth control medications containing both estrogen and progesterone. Additionally, a vaginal ring may not be suitable for women experiencing vaginal irritation or ulcerations. A ring may be accidentally expelled, for example, when it has not been inserted properly, during tampon removal, or while moving the bowels or straining, especially with severe constipation. If this occurs, the vaginal ring can be rinsed with cool to lukewarm (not hot) water and reinserted promptly. If the ring is not replaced within 3 hours of expulsion, then a backup method, such as male condoms and spermicide, should also be used following reinsertion of the ring for at least 7 days.
Medically reviewed by Wayne Blocker, MD; Board Certified Obstetrics and Gynecology
"Overview of the use of estrogen-progestin contraceptives"