What is Birth Control?
Birth control (contraception) is widely used by women who would like to postpone or avoid pregnancy. There are a wide variety of contraceptive methods available for use. This may include intrauterine devices, pills, patches, rings, implants, and injections. Some methods are more effective and longer lasting than others. For example, intrauterine devices have a very high efficacy and can provide contraception for 3-10 years.
Birth control may also be useful in individuals with coexisting conditions such as acne vulgaris or menstrual migraine headache; however, certain conditions preclude the use of estrogen and progestin oral contraceptives.
Who Should Use Birth Control?
Birth control is used by women who would like to postpone or avoid pregnancy. Some methods are more effective and longer lasting than others. For example, intrauterine devices have a very high efficacy and may provide contraception for 3-10 years, depending on the specific type. Birth control may also be useful in individuals with coexisting conditions such as acne vulgaris or menstrual migraine headache. Certain conditions preclude the use of estrogen and progestin oral contraceptives. Common contraindications to estrogen and progestin therapy include:
- Smoking and age ≥35
- Multiple cardiovascular risk factors or ischemic heart disease
- Hypertension or history of stroke
- Venous thromboembolism or hereditary thrombophilia
- Systemic lupus erythematosus
- Migraine with aura
- Breast cancer
- Cirrhosis or hepatocellular cancer
How Does Birth Control Work?
Contraceptives work through various mechanisms to prevent pregnancy depending on the method of birth control. Intrauterine devices prevent pregnancy by a foreign body effect. This occurs due to their plastic or metal frame and as a result of changes caused by local release of either copper Paragard (intrauterine copper contraceptive) or Mirena (levonorgestrel).
Oral contraceptives work through several mechanisms to prevent pregnancy. This includes suppression of gonadotropin-releasing hormone (GnRH) from the hypothalamus, which leads to decreased release of pituitary luteinizing hormone (LH) and follicle stimulating hormone (FSH). Inhibition of the LH surge during mid-cycle prevents ovulation from occurring - this is a key mechanism of action of these methods of contraception.
How Effective is Birth Control?
Various methods of birth control are more effective than others. The most effective therapies include intrauterine devices, contraceptive implants, and sterilization because these result in the lowest pregnancy rates (less than 1 pregnancy per 100 women annually). One of the explanations for their high efficacy is that treatment is minimally influenced by patient compliance. Sterilization includes vasectomy in men or tubal ligation in women – these are permanent methods of contraception.
The next most effective therapies include injectable contraceptives. Oral contraceptives, the transdermal patch, and the vaginal ring are equally effective as long as they are used appropriately and consistently. All of these forms of contraception generally result in 6-12 pregnancies per 100 women annually
Other methods such as diaphragms, cervical caps, male condoms, and withdrawal are the least effective methods for contraception (>18 pregnancies per 100 women annually). Although they can theoretically result in low pregnancy rates, the actual rates of pregnancy are higher due to inconsistent or incorrect use.
What Are My Options for Birth Control?
The various options for contraception include intrauterine devices, oral pills, patches, vaginal rings, subcutaneous implants, and barrier devices. The following will discuss each of these forms of contraception in more detail.
Paragard (Copper IUD) – This form of contraception must be inserted and removed by a clinician. It lasts for 10 years. It does not involve hormone exposure, but may cause heavier menses and unscheduled spotting. It is preferred in women who want long acting contraception and prefer to avoid hormone therapy.
Mirena (levonorgestrel-releasing IUD) - This IUD lasts 3-5 years and uses progestin. It may lead to lighter bleeding and must be inserted and removed by a clinician. It may reduce menorrhagia and dysmenorrhea. It can be associated with spotting.
Contraceptive pill (Ortho Tri-Cyclen), patch, or ring (NuvaRing) – These use estrogen and progestin and cause lighter, predictable withdrawal bleeding. They are contraindicated in women age >35 who smoke or in those with certain estrogen-responsive cancers. They may reduce dysmenorrhea, menorrhagia, and acne vulgaris. The pill is taken daily, the patch is administered weekly, and the vaginal ring is inserted monthly.
Nexplanon (etonogestrel implant) - This is a subcutaneously implanted medication that lasts 3 years and uses progestin. It leads to lighter menses and may be associated with spotting. It requires an incision for removal. It is highly effective for long term contraception in women who want to avoid estrogen.
Depo-Provera (depot medroxyprogesterone acetate) – this is an intramuscular injection that lasts 12 weeks and uses progestin. It leads to lighter periods and is associated with spotting. It requires injection by a clinician. It is an effective option for women who desire long term therapy and want to avoid estrogen.
Side Effects of Birth Control
The side effects of birth control depend on the method of contraception. Intrauterine devices such as Paragard and Mirena can be associated with uterine perforation and an increased risk of pelvic infection in the first 20 days after insertion. The contraceptive pill, patch, or ring is associated with increased risk of venous thrombosis and hepatic adenoma. The Nexplanon (etonogestrel implant) may result in infection or scarring at the insertion and removal site; removal may also be difficult. Depo-Provera (depot medroxyprogesterone) can cause weight gain, mood changes, and osteopenia (long-term use).
- Miller L, Hughes JP. Continuous combination oral contraceptive pills to eliminate withdrawal bleeding: a randomized trial. Obstet Gynecol 2003; 101:653. - https://www.ncbi.nlm.nih.gov/pubmed/12681866
- Legro RS, Pauli JG, Kunselman AR, et al. Effects of continuous versus cyclical oral contraception: a randomized controlled trial. J Clin Endocrinol Metab 2008; 93:420. - https://www.ncbi.nlm.nih.gov/pubmed/18056769
- ACOG Committee on Practice Bulletins-Gynecology. ACOG practice bulletin. No. 73: Use of hormonal contraception in women with coexisting medical conditions. Obstet Gynecol 2006; 107:1453. - https://www.ncbi.nlm.nih.gov/pubmed/16738183
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.