Understanding Birth Control Medications (Contraceptives)

• Birth Control Medications Introduction
• 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
• For More Information
• Web Links
• Synonyms and Keywords
• Authors and Editors

Birth Control Medications Introduction

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. 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:

• Estrogens
  
  
  • Ethinyl estradiol
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  • Mestranol
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• Progesterones
  
  
  • Norethynodrel
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  • Norethindrone
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  • Norethindrone acetate
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  • Norgestimate
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  • Desogestrel
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  • Ethynodiol diacetate
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  • Norgestrel
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  • Levonorgestrel
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  • Drospirenone
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• 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
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  • By altering mucus in the cervix, which makes it hard for sperm to travel further
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  • By changing the endometrium (lining of the uterus) so that it cannot support a fertilized egg
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  • By altering the fallopian tubes (the tubes through which eggs move from the ovaries to the uterus) so that they cannot effectively move eggs toward the uterus
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• 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
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  • History of blood clot disorders
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  • History of stroke or heart attack
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  • Heart valve disease with complications
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  • Severe hypertension
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  • Diabetes that causes blood vessel problems
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  • Poorly controlled diabetes
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  • Severe headaches (for example, migraines)
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  • Recent major surgery with prolonged bed rest
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  • Breast cancer
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  • Liver cancer (or liver disease)
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  • Uterine cancer or other known or suspected estrogen-dependent cancers
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  • Unexplained abnormal bleeding from the uterus
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  • Jaundice during pregnancy or jaundice with prior hormonal contraceptive use
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  • Known or possible pregnancy
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• Drug or food interactions: Contraceptive effectiveness may be reduced by antibiotics, antifungals, anticonvulsants, HIV-fighting 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).
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• Side effects: Birth control may cause a change in vision, necessitating a change in prescription, or an inability to wear contact lens. Birth control pills do not provide protection from sexually transmitted diseases (STDs). The pills must be taken daily and consistently (at the same time every day). If a woman stops taking birth control pills, it may take a few months for her normal ovulatory cycle to return; however, once stopped, a woman can become pregnant even if her 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 lower sexual desire. Additionally, the following more serious side effects 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, heart attack, 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 years and those who smoke more than 15 cigarettes per day.
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  • 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 nonusers. 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. Most doctors currently believe that birth control pill use might interact with another primary cause to stimulate breast cancer.
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  • 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 small.
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  • 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.
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  • Diabetes: Progesterone and high estrogen doses may alter blood glucose (sugar) levels in diabetic women.