Online Medical Reference

Female Contraception

Pelin Batur, MD

Published: December 2016


Unintended pregnancy is a major women’s health problem. In the United States, the unintended pregnancy rate was 45% in 2011 as compared with 51% in 2008.1,2 Although the rate has declined, it is still unacceptably high given the plethora of safe and effective methods of contraception. The consequences of unscheduled pregnancies include delayed prenatal care; early pregnancy exposure to smoking, drinking, or substance abuse; low birth weight; and decreased chances of breastfeeding after delivery.

Condoms and combined oral contraceptive pills (COCs) remain the most commonly used contraceptives. Guidelines strongly recommend long-acting reversible contraceptive (LARC) methods — intrauterine devices (IUDs) and the progestin-only subdermal implant — as first-line options for most women because of their high efficacy. These LARC methods offer women the advantage of not having to remember to take, apply, or insert their contraceptive (worry-free), and not having to rely on a yearly appointment for refills. The 3-year overall continuation rates for LARC users are significantly higher than for other methods, including combined hormonal contraception.3 This article discusses the available female contraceptive methods, including sterilization and emergency contraception, in terms of efficacy, side effects, convenience, and use in clinical practice.

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Contraceptive Use in Clinical Practice

More than 99% of sexually active women have used at least one contraceptive method at some time.4 The choice of contraceptive method is determined by the woman's individual risk factors, age, frequency of sexual activity, number of sexual partners, permanence, and efficacy. (Table 1) shows the effectiveness of the available contraceptives.

Table 1: Effectiveness of Contraceptive Methods
Pregnancies per 100
women in first 12 months
of use

Contraceptive method As commonly used Perfect use
Oral contraceptives
Combined hormonal contraceptives 9 0.3
Progestin-only pills 9 0.3
Transdermal contraceptives
Combined hormonal contraceptives 9 0.3
Vaginal ring
Combined hormonal contraceptives 9 0.3
Injectable contraceptives
Depot medroxyprogesterone acetate 6 0.2
Progestin-only subdermal implant 0.05 0.05
Intrauterine devices  
Levonorgestrel IUD 0.2 0.2
Copper IUD 0.8 0.6
Barrier contraceptives
Diaphragm with spermicide 12 6
Cervical cap
Nulliparous women
Parous women


Female condoms 21 5
Spermicides 28 18
Contraceptive sponge
Nulliparous women
Parous women


Male condoms 18 2
Female sterilization 0.5 0.5
Male sterilization 0.15 0.1
Fertility awareness-based methods
Lactation amenorrhea method 2 0.5
Coitus interruptus 22 4
Symptothermal 0.4
Ovulation method 3
Rhythm method 5
Contraception rate without birth control
No method 85 85

Data from Trussell.5

There is little evidence of benefit for the tests commonly mandated by providers prior to prescribing hormonal contraception. These tests include breast and pelvic exams, cervical and sexually transmitted infection screenings, lab testing, and mammograms.6 For example, in the case of estrogen-containing contraceptives, only a medical history and blood pressure measurement are needed before initiating this contraceptive method — and the measurement can be obtained from a community reading; it does not have to be from the provider’s office. Women should be counseled about the efficacy, side effects, and correct methods of use; about the signs and symptoms that require a return to the provider; and about protection against sexually transmitted infections. After the initial provider visit, a follow-up visit is suggested for counseling and reinforcement, but it is not mandatory.

The Centers for Disease Control (CDC) has several resources for clinicians who prescribe contraceptives. These comprehensive, multidisciplinary recommendations were updated in 2016, and they include the following:

Medical Eligibility Criteria for Contraceptive Use (MEC) provides guidance on which contraceptive is most appropriate for a given patient;7

U.S. Selected Practice Recommendations for Contraceptive Use (SPR) gives practical advice on how to use each contraceptive (eg, initiation, management of missed doses, follow-up).8

The MEC categorizes each contraceptive option into four categories based on a medical problem:

  • Category 1 indicates that there is no restriction for the use of a particular contraceptive method in the setting of a certain personal medical or family history.
  • Category 2 indicates that the advantages of the contraceptive method outweigh the proven risks.
  • Category 3 suggests that the risks may outweigh the advantages, and caution is advised when using that contraceptive method.
  • Category 4 recommends that an alternative contraceptive be chosen because of unacceptable health risks.

Both the MEC and SPR resources are available for free download, including as an application for mobile phones, making them practical for use in clinical practice. The CDC has created a printable table of the MEC guideline. According to the guidelines, most contraceptives can be started if the provider is reasonably certain that the woman is not pregnant. (Box 1) shows the CDC’s published guidelines for determining this.

Box 1. How to be reasonably certain that a woman is not pregnant.8
A healthcare provider can be reasonably certain that a woman is not pregnant if she has no symptoms or signs of pregnancy and meets one of the following criteria:
  • Is ≤7 days after the start of normal menses
  • Has not had sexual intercourse since the start of last normal menses
  • Is ≤7 days after spontaneous or induced abortion
  • Is within 4 weeks postpartum
  • Is fully or near fully breast-feeding (exclusively breast-feeding or the vast majority [≥ 85%] of feeds are breastfeeds), amenorrheic, and < 6 months postpartum

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Combination Hormonal Contraceptives

Hormonal contraceptives contain either an estrogen and a progestin together or a progestin agent alone. There are a variety of mechanisms by which hormonal contraceptives prevent pregnancy. Follicular development and ovulation are prevented by suppression of follicular stimulating hormone (FSH) and luteinizing hormone (LH).The other major contraceptive effect is a change in cervical mucus, causing the production of thick cervical mucus that impairs sperm migration into the cervix. Progestin-only pills inhibit ovulation in only about half of ovulation cycles,7 thus, the thickening of the cervical mucus to prevent sperm penetration plays an important contraceptive role. While endometrial thinning does occur, there is no evidence that prevention of implantation is a contraceptive effect, and these agents do not act as abortifacients.

Hormone Types

On June 10, 1957, the FDA approved the first oral contraceptive, Enovid 10. It contained 9.85 mg of noretynodrel and 150 mcg of mestranol, which is 3 to 4 times the steroids doses in modern oral contraceptives. Lower doses cause fewer side effects, such as headache, breast tenderness, nausea, and hypertension. In particular, lower doses of ethinyl estradiol (EE) are associated with a lower risk of thrombosis. Today, combination pills contain <50 mcg of EE and most contain 20 to 35 mcg, although doses as low as 10 mcg are available. Mestranol is rarely used in oral contraceptives available in the U.S.

Modern contraceptives contain a combination of estrogen and progestin of varying types and doses. These combined hormonal contraceptives (CHCs) are available in a transdermal patch, vaginal ring, or as an oral contraceptive formulation. The progestins are classified by generation, which reflect when they were introduced into the market, and the progestins in each generation often have similar characteristics.

  • First-generation progestins are norethindrone (known as norethisterone in other countries) and ethynodiol diacetate.
  • Second-generation progestins, introduced in the 1970s, are norgestrel and levonorgestrel.
  • Third-generation progestins, added in the 1980s, are desogestrel, norgestimate, and gestodene (not available in the U.S.).
  • The fourth-generation progestin is drospirenone.

Drospirenone differs from the other progestins in that it is derived from 17a-spirolactone. It has antiandrogenic and antimineralocorticoid properties. The antimineralocorticoid effect of drospirenone reduces water retention and bloating. It should not be used in women with hepatic failure, renal insufficiency, or adrenal insufficiency. Women taking nonsteroidal anti-inflammatory agents, potassium-sparing diuretics, angiotensin-converting enzyme inhibitors, angiotensin II-receptor antagonists, or potassium supplements should have their serum potassium levels checked during the first treatment cycle.

Dienogest is the newest type of progestin in the U.S. and has agonistic/antagonistic activity on the human progesterone receptor, androgen receptor, glucocorticoid receptor, mineralocorticoid receptor, estrogen-receptor alpha, and estrogen-receptor beta. In Europe, it has been used for years in combination with EE, but in the U.S., it is available only in combination with estradiol valerate (a synthetic estrogen that is converted to estradiol in a woman’s body).

Combined Oral Contraceptives

The COCs are classified as monophasic, biphasic, triphasic, or quadraphasic pills. The classification depends on the way that the progestin dose is varied throughout the cycle. Monophasic pills have the same dose of estrogen and progestin in all active pills. The other phasic pills have different concentrations of estrogen and progestin varying throughout the pack. Patients sensitive to changes in hormone levels (suffer from headaches, acne, premenstrual dysphoric disorder) should preferentially be treated with a monophasic regimen. In most newer regimens, the patient takes placebo pills for fewer days per month than with older regimens (2-4 days), or the placebo pills have been eliminated. This reduces the number of days of withdrawal bleeding and may improve effectiveness.9 Evidence suggests better suppression of ovulation with continuous (no placebo) or extended (4 periods per year) formulations.9 Although these regimens may be associated with more unscheduled bleeding, women will have less bleeding overall during a year as compared with a classic 21-day hormone/7-day placebo regimen. Though there are formulations specifically designed to create continuous or extended dosing of the pills, a woman may take any pill that she tolerates, as long as the provider makes specific recommendations on the prescription (eg, "Take one pill by mouth daily for 3 packs without a placebo break. Restart same regimen after a 4-day break").

Transdermal Combined Hormonal Contraception

The transdermal contraceptive patch (Ortho Evra) contains 150 mcg of norelgestromin (a metabolite of norgestimate) and 20 mcg of EE. A new patch is applied every week for 3 weeks followed by one patch-free week. Application sites include the buttocks, abdomen, outer arms, and torso, but not the breasts. The patch may be a good option for women who have difficulty adhering to other hormonal contraceptive regimens.

The patch exposes women to higher levels of estrogen than most COCs. The FDA has added new warnings that users could have twice the risk of blood clots than with COCs due to higher levels of estrogen exposure (although evidence for this is mixed). Providers must balance the higher estrogen exposure against the chance of unintended pregnancy and method convenience.

The patch completely detaches in 2% to 6% of cases. If it is replaced within 48 hours, no backup contraception is needed. If the patch-free interval exceeds 2 days, a new patch should be placed, and a backup contraceptive method should be used for 7 days. Emergency contraception should be considered prior to restarting the patch. If the delayed application or detachment occurred during the third patch week, then the hormone-free week should be omitted by finishing the third week of patch use. In case of skin irritation, the patch should be removed and a new patch applied to another site. Women weighing more than 198 pounds should use caution when using the patch because its effectiveness may be reduced.

Vaginal Ring

The NuvaRing is a nonbiodegradable, flexible vaginal ring made of a polymer that contains ethylene vinyl acetate and magnesium stearate. The outer diameter of the ring is 54 mm, and the cross-sectional diameter is 4 mm. It releases 120 mcg of etonogestrel (a metabolite of desogestrel) and 15 mcg of EE daily. The ring is left in place for 3 weeks, followed by 1 ring-free week to induce menstruation. Efficacy is similar to that of COCs if used as directed. Vaginal discharge, vaginitis, and irritation can occur. Side effects are otherwise similar to those of COCs.

If the ring is expelled during the first 3 weeks of use, it should be washed with lukewarm water and then reinserted. If the ring-free interval is longer than 3 hours, a backup contraceptive method should be used concomitantly for 7 days. The ring should never be left in place for more than 4 weeks. When used in a continuous fashion, a new ring is placed every 4 weeks avoiding a withdrawal menses.

Safety Considerations

There are several contraindications for these CHCs. The estrogen component increases hepatic production of factor VII and X as well as fibrinogen. Therefore, the risk of thromboembolic phenomena is increased. These drugs should not be used in women who have an active thromboembolic event or stroke or who have a familial hypercoagulation disorder. In addition, they should not be used in women with certain liver diseases, a history of estrogen-dependent tumor, undiagnosed abnormal uterine bleeding, and in women over age 35 who smoke. The CDC Medical Eligibility Criteria7 should be consulted prior to prescribing contraceptives to women with chronic medical conditions. For example, women with focal nodular hyperplasia of the liver may take any contraceptive safely, while those with hepatocellular adenoma should preferentially use a copper IUD to avoid hormone exposure.

Many providers are unaware that a family history of breast cancer is a category 1 for the use of all contraceptives (meaning no restrictions), including hormonal contraceptives. A meta-analysis of BRCA1/2 mutation carriers showed no increased risk for breast cancer with modern oral CHC regimens but a significantly reduced risk for ovarian cancer.10 Therefore, even patients at highest risk for breast cancer may opt to use CHCs after a thorough discussion of risks versus benefits with their provider.

A diagnosis of migraine is another important consideration. Because most women experience an exacerbation of headaches during menses, continuous CHCs can mitigate this phenomenon. According to a 2015 Cochrane review, studies show that stroke risk is not significantly increased with today’s low dose CHCs containing <30 µg ethinyl estradiol.11 However, the use of CHCs in the setting of migraine with aura is restricted by current guidelines due to concerns of increased stroke risk—concerns that originated in the era of high-dose contraceptives. Therefore, a detailed history is needed prior to prescribing CHCs in women with a history of headache.

In an otherwise healthy, nonsmoking woman older than 35 years, the use of CHCs is safe. Perimenopausal women in particular may benefit from the reduction in irregular bleeding and vasomotor symptoms that accompanies the use of CHCs. Testing to confirm menopause is not reliable due to hormonal fluctuations in perimenopausal women; thus, CHC users may continue using these contraceptives until they are 50 to 55 years old, with annual assessment of risks and benefits.

The use of CHCs by diabetic women should be limited to those who do not have evidence of vascular disease, other end organ dysfunction (ie, nephropathy, retinopathy, neuropathy), and have had diabetes for less than 20 years duration. Progestin-only methods may be more appropriate for women who have contraindications to estrogen (ie, arterial or venous thromboembolic disease).

Although there are only a few contraindications for progestin-only methods, FDA-approved package labeling often is the same as that for combined estrogen/progestin methods. For example, the package insert for norethindrone progestin-only oral contraceptive and depot medroxyprogesterone list a history of thromboembolism as a contraindication to usage. This contraindication is not supported by the literature or CDC guidelines. However, patients with a medical condition that makes unintended pregnancy unsafe for the mother or the fetus should be encouraged to use contraceptives with the highest effectiveness, such as progestin only arm implants or IUDs.

Side Effects and Precautions

Oral contraceptive pills should be taken at the same time each day. Nausea, spotting, amenorrhea, decreased libido, and breast tenderness are among the potential side effects. However, many symptoms will subside with continued use. Irregular unscheduled bleeding is a common complaint and causes discontinuation in many first-time users. The public perception of weight gain associated with CHCs is not supported by the data. Various studies have found no significant differences in weight gain between users and non-users.12 Overall, most CHC users have no side effects and the vast majority of the side effects experienced are minor.

In a 2011 Cochrane review, the types of progestins in low-dose combined hormonal contraceptives were compared for their effectiveness and side effects.13 Although no significant differences in pregnancy rates were noted, monophasic second- and third-generation pills were less likely to be discontinued than first-generation ones; however, the overall quality of the trials was low.

Contrary to popular belief, antibiotic usage is not associated with contraceptive failure. Recent studies have shown that the only antibiotic that can decrease the effectiveness of COCs is rifampin, which induces the liver enzymes that metabolize the steroids.7,8 There is evidence that antiretrovirals may also decrease the steroid level; the 2016 CDC guidelines can provide specific recommendations for taking care of women with HIV.8

Some anticonvulsants have been shown to decrease the effectiveness of COCs by the same mechanism. This is seen with phenobarbital, phenytoin, carbamazepine, oxcarbazepine, felbamate, topiramate, and vigabatrin. It is not seen with ethosuximide, gabapentin, lamotrigine, levetiracetam, tiagabine, valproic acid, or zonisamide. Implants and IUDs are the preferred methods in these women.

Postpartum women should avoid the use of CHCs for the first 20 days following delivery due to the high risk for venous thromboembolism (VTE) during this period. After 42 days postpartum, CHCs may be safely started, even if breast-feeding. Between days 21 and 42, whether a woman can start a CHC depends on her other factors for VTE (irrespective of whether she is breast-feeding), These risk factors include age older than 35 years, previous VTE, thrombophilia, immobility, transfusion at delivery, peripartum cardiomyopathy, BMI ≥30 kg/m², postpartum hemorrhage, post-cesarean delivery, preeclampsia, or smoking.

Thrombotic Risks

Although all CHCs carry an increased risk of thrombotic events, the risk is overall relatively low. Contraceptives reported to have higher relative risk of VTE events compared with others include the etonogestrel vaginal ring (NuvaRing), contraceptive patch (Ortho Evra), and several COCs containing third-generation progestins, including gestodene, desogestrel, and drospirenone (DRSP).14-16

Of these, there has been most controversy with DRSP products. However, two recent controlled, prospective, observational studies of more than 50,000 women in the US and Europe showed no increase in risk of arterial or VTE in DRSP users compared with other COCs.17,18 The US product label was updated in April 2012 to state that COCs containing DRSP may be associated with a higher risk of VTE than COCs containing levonorgestrel or other progestins.19

In November 2012, the American College of Obstetrics and Gynecology (ACOG) released a committee opinion stating that although DRSP-containing pills may have a higher risk of VTE, the risk of VTE is increased among users of any COC (3-9/10,000 woman years) when compared with nonusers (1-5/10,000 woman-years).20 In real numbers, the absolute risks of VTE in DRSP users would be 10 to 11 per 10,000 woman years (as compared to 3-9/10,000 woman years in other COC users). This risk is very low and is lower than the risk of VTE during pregnancy (approximately 5-20/10,000 woman years) and the postpartum period (40-65/10,000 woman years).

Noncontraceptive Benefits of Oral Contraceptives

Oral contraceptives have been successfully used to treat hyperandrogenism, including idiopathic hirsutism and polycystic ovary syndrome. Most COCs are effective at treating acne by elevating sex hormone-binding globulin and consequently decreasing circulating testosterone;21 however, only a few manufacturers have sought FDA approval for this indication.

Women using CHCs typically have a lighter menstrual flow for a shorter number of days than nonusers and have reduced incidence of iron deficiency anemia. Thus, CHCs are used to treat dysmenorrhea, menorrhagia, and endometriosis. They also are useful for treatment of women with a history of irregular menses, such as hypothalamic amenorrhea, polycystic ovarian syndrome, and the perimenopausal woman. They can reduce the symptoms associated with premenstrual dysphoric disorder. Because they inhibit ovulation, CHCs are useful in the suppression of ovarian cysts. Postmenopausal hip fracture rates are reduced in women who used combined contraceptives in their 30s. Use of CHCs is also associated with reduced rates of benign breast disease, ovarian, colon, and endometrial cancers. CHCs are often used in perimenopausal women to relieve vasomotor symptoms.

Progestin-Only Pills

Progestin-only pills (or mini-pills) are associated with more breakthrough bleeding than CHCs. Simply for contraceptive purposes, current guidelines note similar efficacy to CHCs. However, progestin-only pills have a shorter half-life than CHCs and must be taken consistently and on time to ensure contraceptive efficacy and minimize abnormal bleeding; delaying ingestion by as little as 3 hours can decrease efficacy in contrast to COCs. The only mini-pill available in the US contains 35 mcg of norethindrone. Irregular bleeding and breast tenderness are the most common side effects. Though progestin-only pills are a good option for patients who need to avoid estrogen, these women usually have medical conditions that make unintended pregnancy unsafe for the mother or fetus. Thus, they should be encouraged to use methods with the highest effectiveness, such as a progestin-only arm implants or IUDs.

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Injectable Contraceptives

Depot Medroxyprogesterone Acetate

Depot medroxyprogesterone acetate (DMPA; Depo-Provera) is a progestin that prevents ovulation in addition to causing changes in cervical mucus and the endometrium. It is administered as an injection of 150 mg in the buttocks or upper arm and is repeated every 3 months (13 weeks). There is also a formulation in which 104 mg is injected subcutaneously in the upper thigh or abdominal wall area by the patient. This is also injected every 3 months (13 weeks). The injection can be administered up to 2 weeks late (ie, 15 weeks after the last injection) without the need for a protective back-up contraceptive method. There are no limits on how early a patient can return for injection. If the woman is >2 weeks late, she can have the injection if it is reasonably certain that she is not pregnant. She needs to abstain from sexual intercourse or use additional contraceptive protection for the next 7 days. If a woman is >2 weeks late for injection and it cannot be determined that she is not pregnant, then it is best to order a pregnancy test. If negative, have the patient abstain from intercourse for 2 weeks and return for the injection (with a repeat pregnancy test performed prior to injection). It is important to remember that barriers to contraceptive use, such as the need for return visits, can increase the chance of unintended pregnancy.

Side effects include irregular bleeding, weight gain (average 2 kg), headache, mood change, abdominal pain, and breast tenderness. After 1 year of use, approximately 50% of women have amenorrhea. Use of DMPA is safe, reversible, maintains spontaneity, and has noncontraceptive benefits similar to those of CHCs. There is reduced menstrual cramping and pain, fewer periods, and lower chance of anemia. Fertility usually returns within 6 to 9 months after stopping but can take up to 18 months.

The DMPAs work by suppressing ovulation and estradiol production. Advise patients taking DMPA to exercise and take adequate amounts of calcium. In 2004, the FDA issued a black box warning for DMPA discouraging its use for longer than 2 years because the longer use could lead to bone loss from which the woman may only partially recover. In 2008, ACOG issued a statement indicating that DMPA can be used for longer than 2 years, if clinically indicated.22 According to the ACOG recommendations, while DMPA has been associated with bone loss, it is usually temporary and the amount of loss is similar to that of other causes, such as pregnancy and breast feeding.

The evidence suggests that the bone mineral density will most often return to baseline levels by 1 to 2 years after stopping DMPA in women with adequate endogenous estrogen levels.22-24 There is no need to monitor bone density in women taking DMPA. The advantages of DMPA outweigh the theoretical risks, and there should be no arbitrary cutoff on length of use, particularly in adolescents. For women who are concerned about bone health, it is important to remember that LARC methods provide a worry free alternative to those who may have chosen DMPA because they have difficulty remembering to take, apply, or insert their contraceptive.

Implantable Contraceptives

The Nexplanon single-rod progestin implant is placed subdermally in the inner arm and provides continuous release of etonogestrel (a metabolite of desogestrel) for 3 years. Nexplanon works by suppressing ovulation and is one of the most effective forms of birth control, with a failure rate of 0.05%. This effectiveness is better than many forms of sterilization. The implant requires no user action and does not inhibit spontaneity. Nexplanon is identical to the first-generation implant that was introduced in 2006 (Implanon), but Nexplanon is radio-opaque and hence can be localized by an ultrasound and x-ray, and also has an insertion device that is easier to use.

Side effects include spotting, irregular bleeding, and amenorrhea. Irregular bleeding is the primary reason for discontinuation. However, continuation rates for LARC methods are higher than for other methods, such as DMPA and CHCs, at 1 and 3 years follow-up. Fluid retention, weight gain, and breast tenderness are less common.

Potential complications of insertion include infection, hematoma formation, and local irritation or rash. Deep insertions into muscle with the Implanon device can lead to possible migration of the implant. The Nexplanon inserter makes deep insertions significantly less likely. Insertion and removal are simple procedures that can be done in most practitioner office settings. Ovulation resumes shortly after removal. The FDA has mandated that providers undergo specific training to place and remove the devices, which is available from the implant manufacturer, Merck. The implant can be placed any time if it is reasonably certain that a woman is not pregnant.

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Intrauterine Devices

Current intrauterine devices (IUDs) are safe and significantly more effective than CHCs (Table 1). Adult and pediatric society guidelines endorse offering IUDs as a first-line contraceptive option for appropriate patients, including adolescents and nulliparous women.25,26 The copper IUD induces a foreign-body reaction in the endometrium and cervical mucus that prevents viable sperm from reaching the fallopian tubes. It has an effective life of 10 years. Expulsion of the copper IUD may occur in up to 5% of women during the first year.27 The user can be taught to detect expulsion. There are many copper IUDs available internationally, but only one is available in the US (ParaGard).

The levonorgestrel (LNG)-releasing IUDs work predominantly by causing changes in cervical mucus quantity and quality as well as changes in tubal transport of sperm and egg. In the first year of use, ovulation may be inhibited; however, after that, most cycles are ovulatory. Three LNG-releasing IUDs are available in the US: Liletta, Mirena, and Skyla. With Mirena and Liletta, 20 mcg/day of LNG is released, and the IUD is kept in place for 5 and 3 years, respectively. The LNG level with Mirena decreases progressively to half that value after 5 years. (Studies with Liletta use over 5 years are being conducted but as of this writing, it is not approved for the longer time frame.) Skyla, which is slightly smaller, releases approximately 6 mcg LNG per day over its 3-year lifespan.

Determination of plasma estradiol and progesterone levels indicates that women using Mirena generally have normal ovulatory cycles; however, unlike women who use the copper IUD, Mirena users tend to have significantly decreased menstrual flow. The rate of amenorrhea in women who have used the device for longer than 12 months is 20% to 80%. Mirena is approved for the treatment of heavy menstrual bleeding.

Side effects associated with IUDs include cramping during insertion, bleeding, and perforation of the uterus. Overall perforation rates are 1.4 vs 1.1 per 1000 insertions in LNG vs copper IUDs, respectively. Breast feeding at the time of insertion and insertion <36 weeks following the last delivery are risk factors for perforation.28 Perforation rates in parous, non–breast-feeding women are even lower at 1.0 and 0.5 per 1000 in LNG vs copper IUD users, respectively. When they do occur, perforations tend not to be associated with serious illness or injury such bowel/bladder injury, septicemia, or peritonitis. Though there is a mildly increased risk of ectopic pregnancy, overall ectopic pregnancy rates in IUD users are lower because of increased effectiveness in preventing pregnancy. Use of an IUD does not increase the risk of pelvic inflammatory disease beyond the first month after insertion (the increase in the first month is likely related to the procedure). Women who are at increased risk for sexually transmitted infections can have screening cultures at the time of their IUD insertion. There is no reason to remove the IUD for a positive culture unless the infection is refractory to treatment.

Overall, the IUD is an excellent contraceptive choice with few contraindications. It is not user dependent, spontaneity is maintained, it is >99% effective (first-year failure rate for the 5-yr LNG IUD is 0.06%; the copper IUD is 0.52%),29 and fertility returns rapidly after discontinuation of the device. Any IUD can be inserted when one is reasonably certain that the woman is not pregnant. A copper IUD also can be inserted within 5 days of unprotected intercourse (see Emergency Contraception).

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Barrier Contraceptives

The barrier methods currently available in the US are listed in (Table 2). Outside of the male condom, these methods work by covering the cervix and preventing sperm entry. These devices are significantly less effective than other forms of contraception. This decreased efficacy is partially due to the dependence on correct placement by the patient as well as consistent usage. They are not optimal forms of contraception when used alone, but they can increase effectiveness of pregnancy prevention when used in combination with other methods. The advantages of these methods include that they are non-hormonal, have moderate protection against STIs, and are immediately reversible.

Side effects of barrier methods include vaginal irritation; allergic reactions to latex, silicone, or spermicide; urinary tract infections; and the rare risk of toxic shock syndrome if the device is left in place for too long. These methods are safe and have no effect on the menstrual cycle.

Table 2: Select Barrier Contraception Methods Available in the U.S.
Method Left in place after intercourse (hours) Remove within (hours)
Diaphragm 6 24
Cervical cap (FemCap) 8 48
Female condom (FC2) Remove immediately
Contraceptive sponge 6 30


The diaphragm is a shallow dome-shaped silicone or latex disk with a flexible rim (Figure 1). It sits against the pubic bone in the vagina and covers the cervix. Effectiveness depends on the proper fit as determined by the practitioner. It requires a prescription and an in-office “fitting” to train the patient in insertion and removal. Refitting is needed if there is a pregnancy or the patient’s weight changes by more than 10 pounds. Caya, a one size fits all diaphragm, is available online. Diaphragms are considered to be more effective than cervical caps.

Spermicide jelly should be applied to the diaphragm dome before use. If intercourse recurs within 6 hours, additional spermicidal jelly should be applied to rim of diaphragm while it is still in the vagina (without removing the diaphragm). The diaphragm must remain in place for 6 hours after intercourse but not for longer than 24 hours. With the Caya diaphragm, if it was placed more than 2 hours before intercourse, a repeat dose of spermicide is inserted using an applicator. Caya is a silicon-based product, so it should not be used with a silicone-based lubricant; only water-based lubricants are recommended. Diaphragm use is associated with an increased incidence of urinary tract infections, and if left in place for more than 24 hours, it increases the risk for toxic shock syndrome.

Cervical Cap

The cervical cap is smaller than a diaphragm. It fits securely in the vagina, covering the cervix, and must be fitted by a physician. The only brand available in the US is the FemCap (Figure 2), and it comes in three sizes, ranging from 22 mm to 30 mm. The sizing is determined by parity history. Women who have never been pregnant will use the 22 mm size. Women who have miscarried, had termination (even after 2 weeks of pregnancy), or had a cesarean section will use the 26 mm size. Women who had a vaginal delivery will use the 30 mm size. If there is any question about whether a woman has ever been pregnant, it is best to use the 26 mm. This method is less effective in women who have had a vaginal delivery; it is a better choice for women who are nulliparous. The patient needs to be trained in insertion and removal. Spermicide is placed inside the bowl and the groove around the outside of the device. There is no need to insert more spermicide with additional acts of intercourse. The cap can be inserted up to 8 hours before intercourse and should remain in place for no longer than 48 hours.

Female Condom

The female condom consists of a lubricated nitrile sheath 6.5 inches in length with a flexible ring on each end. One ring is inserted into the vagina much like a diaphragm, while the other remains outside, covering the labia, preventing the condom from becoming dislodged. Side effects include irritation and allergic reactions. This is the only woman-controlled method that reduces the risk of transmission of STIs, including HIV, and it is available over-the-counter. The product can be used during menses and in women with a latex allergy. Effectiveness increases in those with excellent adherence. The most common complaint is difficulty with insertion. Older versions were noisy during intercourse, reported to be resolved with the newer version. If noise does occur, it can be reduced by adding additional lubrication. This method is used by <1% of women in the U.S. The female condom can be inserted up to 8 hours before intercourse, but should be removed and discarded immediately after intercourse. It should not be used with male condoms because friction can pull out the female condom.


Spermicides are a chemical barrier method containing nonoxynol-9, which kills sperm or renders them inactive. Spermicides come in the form of foam, cream, gel, suppository, and contraceptive film. Side effects include irritation, allergic reaction, and urinary tract infections. Spermicides are inexpensive and do not require a prescription. They offer some protection against STIs, but are less effective as a contraceptive than other methods. Unintended pregnancy rates with spermicide use alone are similar to that of the withdrawal (pulling out) method, with approximately 1 of 5 women having an unintended pregnancy each year.5 Ideally, spermicides should supplement mechanical barrier methods and should not be used as a sole source of contraception.

Contraceptive Sponge

The contraceptive sponge is a soft polyurethane sponge impregnated with nonoxynol-9 spermicide. The soft nature of the product causes it to feel like vaginal tissue so that it is not noticed by the partner. It is designed to gradually release the spermicide over a 24-hour period without the need for additional spermicide, should repeated intercourse take place. The effectiveness of the sponge varies. Under typical conditions for nulliparous women, 12% of women will have an unintended pregnancy in 1 year; the rate is 24% for parous women. Under ideal conditions, effectiveness is likely higher: 9% failure rate each year for nulliparous women and 20% for parous women.5 Similar to the cervical cap and diaphragm, the sponge should be kept in place for at least 6 hours after intercourse to ensure effective contraception. However, it should not be left in place for more than 30 hours after insertion. It is available without a prescription.

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Female Sterilization

Hysteroscopic Sterilization

Hysteroscopic sterilization is a method of permanent sterilization that uses a transcervical approach. The micro-insert consists of a stainless steel inner coil, an elastic outer coil, and polyethylene fibers. The coil is inserted into the uterine end of the fallopian tube using a hysteroscopic technique. The outer coil expands to anchor the insert. The polyethylene fibers expand and cause inflammation and extensive fibrosis, resulting in permanent occlusion of the fallopian tubes by 12 weeks. Failure to correctly place the micro-inserts can lead to expulsion. Women should use a backup method for 12 weeks. Hysterosalpingography must be done at the end of 12 weeks to confirm tubal occlusion. Patients who are allergic to nickel may have an allergic reaction to this device.

The advantage over traditional sterilization is that hysteroscopic sterilization can be performed in an office setting under local anesthesia. Side effects include pain during and after insertion, as well as risk of failure, and a small increased risk of ectopic pregnancy should a failure occur. The failure rate for hysteroscopic sterilization was originally reported to be less than 0.2%. However, with more real world experience, the expected unintended pregnancy rates may be as high as 96 per 1000 women at 10 years.30

Tubal Ligation

Tubal ligation is a surgical procedure requiring general or regional anesthesia in which the fallopian tubes are occluded. It is the most common surgical procedure performed on women and the most common form of contraception in women older than 35 years. This is accomplished by surgically removing a portion of the tube and applying an inert clip or using electrocautery to destroy a section of tube. This can be accomplished in the immediate postpartum period as well as during an interval procedure. Although it can be performed as an open procedure, it is usually accomplished laparoscopically or via a small infra-umbilical incision during the postpartum period. The surgery takes about 30 minutes. Tubal ligation does not affect the menstrual cycle and is not associated with painful menses or more frequent or heavier menses. It has the usual risks of surgery, such as bleeding, infection, side effects of anesthesia, and bowel or bladder injury. The failure rate is about 1 out of 200 in the first year after the procedure with an increased risk of ectopic pregnancy, should a failure occur.

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Fertility Awareness-Based Methods

Fertility awareness-based methods (also called FAMs or natural family planning) restricts intercourse to naturally infertile periods. Various methods are used to identify these infertile periods. The method begins with the knowledge that sperm can live in the female reproductive tract for up to 6 days, whereas the egg can survive for 24-48 hour after ovulation. This method is effective for women who have menstrual cycles between 26 and 32 days. This is not appropriate for women with irregular periods (especially teens), frequent abnormal discharge, or those whose partner is not willing to abstain at least 7 days each month. The typical effectiveness is difficult to predict but is reported to be approximately 76% to 88%, although perfect use likely can yield higher effectiveness rates. Careful instruction is needed to make FAMs successful. There are multiple types of FAMs, which are more effective if used in combination.

The standard days method requires a woman to avoid unprotected intercourse on days 8 to 19 of the menstrual cycle. Studies of daily hormonal assessments show that the timing of the 6-day fertile window does vary greatly, even in women with regular menstrual cycles.

With the cervical mucus and 2-day methods, cervical mucous is checked daily and tracked. Mucus becomes copious, stretchy, and clear at the time of ovulation. Intercourse will need to be avoided depending on the nature of the mucous.

The symptothermal method combines multiple FAMs, including assessment of daily basal body temperature and consistency of cervical mucus. Body temperature rises 2 days before ovulation; however, it only rises by 0.4°F to 1°F and it can be influenced by illness. It is important to remember that the temperature must be taken at the same time every day.

The lactation amenorrhea method is based on natural postpartum infertility, when a woman is amenorrheic and exclusively breastfeeding. The infant's suckling suppresses production of hormones. All three criteria—exclusive or nearly exclusive breast-feeding, no menses since delivery, and <6 months postpartum—must be satisfied to effectively use this method. It has about 25% failure rate in the first year.

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Emergency Contraception

Approximately half of U.S. pregnancies are unintended, despite the availability of a range of highly effective ongoing contraceptive methods. A wide spectrum of circumstances may lead to unprotected sex, including an individual’s lack of access to ongoing contraception, forced sex or reproductive coercion, lapses in contraceptive use, or contraceptive failure. Emergency contraception (EC) provides a chance to prevent pregnancy after intercourse.

In the U.S., four options for EC are available:

  • Levonorgestrel (LNG) 1.5 mg pill (a progestin-only method),
  • Ulipristal acetate (UPA) 30 mg pill (a progesterone-receptor modulator),
  • Oral contraceptive pills in various combinations (depends on pill formulation), known as the Yuzpe method,
  • Copper IUD.

All of these methods can be used within 5 days of intercourse, but they should be used as soon as possible for highest efficacy.

The copper IUD is the most effective form of EC, with 99% reported efficacy. Among the oral methods, UPA is the most effective. The Yuzpe regimen is the least effective method and has the most side effects (nausea, vomiting). Because of its short duration of use, there are no contraindications to the use of an oral EC; the typical contraindications to CHCs do not apply to EC. The most effective EC methods (copper IUD and UPA) are only available via a provider. Although LNG-based EC is now available without a prescription, women who are overweight or obese have a higher chance of unintended pregnancy with this product and should use the most effective methods.31

Worldwide experience with the oral EC products has shown that they are not teratogenic. Thus, a pregnancy test is not required before treatment. All oral EC pills work by preventing ovulation. They will not disrupt an already established pregnancy and are not an abortifacient. Studies show that the oral EC products available in the U.S. are not effective after ovulation has occurred.

The most common side effects include nausea, vomiting, and delayed menses. If vomiting occurs within 3 hours of taking EC pills, a repeat dose should be taken as soon as possible. A woman should be advised to take a pregnancy test if she has not had a withdrawal bleed within 3 weeks of using EC.

If needed, EC can be used more than once in the same month. However, women requiring frequent use of EC should also be counseled about effective methods of ongoing contraception that do not require frequent attention, such as LARC methods. Any regular contraceptive method can be started immediately after the use of LNG EC or the Yuzpe regimen. After the use of UPA, when to restart regular contraceptive depends on the contraceptive. Women who use a hormonal contraceptive should consider restarting it 5 days after taking UPA (given the UPA can decrease the effectiveness of CHC). A woman will either need to abstain from sexual intercourse or use a barrier contraceptive for 7 days after resuming her regular contraceptive, or until her next menses, whichever comes first. The CDC Selected Practice Recommendations8 helps provide very specific guidance for providers on when regular contraceptives can be restarted after the use of UPA (also available on the CDC SPR mobile application).

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The range of available contraceptive options has increased markedly, and is likely to continue increasing as consumers seek safer, more-effective contraceptive methods. Improved counseling and knowledge should lead to more consistent and correct use of contraceptives and decreased numbers of unplanned pregnancies.

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  • Approximately half of all pregnancies are unplanned leading to poor outcomes for both mother and child, making unintended pregnancy a major health problem.
  • The most effective contraceptive methods are the progestin-only arm implant and intrauterine devices.
  • Barrier methods of contraception are less effective when used as a sole source of contraception.
  • The CDC Medical Eligibility Criteria for Contraceptive Use helps provide guidance on which contraceptive is most appropriate for a given patient
  • The CDC US Selected Practice Recommendations for Contraceptive Use is a resource that gives practical advice on how to use each type of contraceptive

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Suggested Readings

  • Grimes DA, Lopez LM, O'Brien PA, Raymond EG. Progestin-only pills for contraception. Cochrane Database Syst Rev. 2013; 11:CD007541.
  • Kost K, Unintended Pregnancy Rates at the State Level: Estimates for 2010 and Trends Since 2002. New York, NY: Guttmacher Institute, 2015. Available at
  • Gipson JD, Koenig MA, Hindin MJ. The effects of unintended pregnancy on infant, child, and prenatal health: a review of the literature. Stud Family Plann 2008; 39:18-38.
  • Wu CQ, Grandi SM, Filion KB, et al. Drospirenone-containing oral contraceptive pills and the risk of venous and arterial thrombosis: a systemic review. BJOG 2013; 120:801-811

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  3. Diedrich JT, Zhao Q, Madden T, Secura GM, Peipert JF. Three-year continuation of reversible contraception. Am J Obstet Gynecol 2015; 213:662.
  4. Mosher DK, Jones J. Contraceptive methods women have ever used: United States, 1982–2010, National Health Statistics Reports, 2013, No. 62. Available at Accessed September 21, 2016.
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  11. Roach RE, Helmerhorst FM, Lijfering WM, Stijnen T, Algra A, Dekkers OM. Combined oral contraceptives: the risk of myocardial infarction and ischemic stroke. Cochrane Database System Rev 2015; 8:CD011054.
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Pelin Batur, MD; nothing to disclose.