The main behavior-based, fertility-awareness methods are, naturally, entirely user-dependent. First-year failure rates are around 20% for the ovulation and symptothermal methods, with the standard days and calendar rhythm methods showing slightly lower failure rates of 12% to 13% [4]. Some sources give failure rates as high as 35.3% (Table 1) [8,59]. None of these methods protect against STIs [4].

The diaphragm is a rubber cup that is placed at the end of the vagina with the posterior rim in the posterior fornix and the anterior rim behind the pubic bone. Spermicide is placed on the inner surface, ensuring its application next to the cervix. Unlike male and female condoms, diaphragms must be fitted by a healthcare practitioner [4]. When used with spermicide, the diaphragm provides some protection against bacterial and viral STIs, but not nearly to the extent that more extensive, skin-covering barrier methods such as condoms provide [9]. The concomitant use of spermicide is recommended, although large-scale studies to prove increased efficacy have not been conducted [4].

Once inserted, the diaphragm is considered effective for six hours. The device must be left in place for six additional hours after intercourse. If it is left in place for longer than six hours total, it is recommended to apply additional spermicide. Due to risk of toxic shock syndrome, use for longer than 24 consecutive hours is not recommended [4].

The device consists of a polyurethane sponge containing nonoxynol-9. It is moistened with water and placed in the vagina, with the dimpled surface against the cervix. The outer surface has a ring for removal. The sponge may be worn for 24 hours and must be left in place for 6 hours after intercourse [4].

The estrogen component of COCs inhibits follicle-stimulating hormone (FSH) and endometrial proliferation, providing cycle control. The progesterone component provides the main contraceptive effect, inhibiting the luteinizing hormone (LH) surge that triggers ovulation and thinning of the endometrium; it also thickens cervical mucus, which inhibits sperm motility and function [9,12]. Combined, they suppress ovulation and produce a thin, asynchronous endometrium with decreased tubal mobility [12]. Almost all COCs in the United States use ethinyl estradiol for their estrogen component, although a newer estradiol-based contraceptive, Natazia (estradiol valerate and dienogest), was approved by the FDA in 2010 [9,16,18].

There are many different types of progesterone used in COCs, and their androgenic effects have a wide range. The three progestins that have the lowest androgenic side-effect profile are norgestimate, desogestrel, and drospirenone. Progestins with higher androgenicity may increase acne and may antagonize estrogen's beneficial lipid profile to a greater degree. For patients experiencing these side effects or for patients who have acne or hyperlipidemia to begin with, a less androgenic progestin is indicated. Desogestrel and drospirenone, however, seem to have a higher risk of VTE compared with levonorgestrel, a more androgenic progestin [9,17]. Drospirenone is a derivative of spironolactone and has antimineralocorticoid effects. It is beneficial for acne and has an indication for premenstrual dysphoric disorder (PMDD), but it must not be used with spironolactone or daily nonsteroidal anti-inflammatory medications, or for patients with renal, adrenal, or hepatic compromise. It is recommended to check serum potassium in any woman on drospirenone and a second medication that may affect potassium levels (e.g., heparin, angiotensin converting enzyme inhibitors, diuretics) [18].

There are many different types of progesterone used in COCs, and their androgenic effects have a wide range. The three progestins that have the lowest androgenic side-effect profile are norgestimate, desogestrel, and drospirenone. Progestins with higher androgenicity may increase acne and may antagonize estrogen's beneficial lipid profile to a greater degree. For patients experiencing these side effects or for patients who have acne or hyperlipidemia to begin with, a less androgenic progestin is indicated. Desogestrel and drospirenone, however, seem to have a higher risk of VTE compared with levonorgestrel, a more androgenic progestin [9,17]. Drospirenone is a derivative of spironolactone and has antimineralocorticoid effects. It is beneficial for acne and has an indication for premenstrual dysphoric disorder (PMDD), but it must not be used with spironolactone or daily nonsteroidal anti-inflammatory medications, or for patients with renal, adrenal, or hepatic compromise. It is recommended to check serum potassium in any woman on drospirenone and a second medication that may affect potassium levels (e.g., heparin, angiotensin converting enzyme inhibitors, diuretics) [18].

The risk of thrombotic stroke and myocardial infarction is also increased in women on estrogen-containing contraceptives. Although these risks remain low in terms of absolute risk, the relative risk is higher with higher oral doses of estrogen (i.e., ≥50 mcg) and with the patch and ring delivery systems [24]. Smoking, hypertension, and diabetes all increase the risk for cardiovascular disease, although they do not directly increase clot risk [19,25]. In women with hypertension taking COCs, the relative risk of acute myocardial infarction increases by a factor of twelve compared with those women not using COCs; despite this, the absolute risk of myocardial infarction remains low. Non-contraceptive benefits of COCs should also be considered in these patients when making the decision to prescribe oral contraceptives. Non-estrogen-containing methods may be preferred.

According to the World Health Organization (WHO), there are no restrictions for COC use in women with mild, compensated cirrhosis, chronic viral hepatitis, or carriers of the hepatitis virus. In women with acute hepatitis, the risks usually outweigh the benefits for initiating use of COCs. However, COC use is contraindicated in women with severe liver disease [23,32]. Symptomatic gallbladder disease is also a relative contraindication [9]. Undiagnosed genital tract bleeding is a contraindication to COC use [12]. Pregnancy should always be ruled out if bleeding occurs while on a hormonal contraceptive.

The progesterone injection, depot medroxyprogesterone acetate (DMPA), is typically given as a 150-mg intramuscular injection once every three months. The progesterone acts to suppress ovulation by inhibiting the hypothalamic-pituitary-ovarian axis and also thins the endometrial lining [37]. This produces the unwanted side effect of unpredictable bleeding for the first several months but often leads to amenorrhea in the long term [9]. This can be useful in women with menorrhagia from leiomyoma, and DMPA is often used for this purpose. It can be used to temporize, or even prevent, hysterectomy for this indication [19]. DMPA is also often used for the management of endometriosis-related pain. Women on the contraceptive injection experience a decrease in dysmenorrhea, ovarian cysts (better than low-dose pills), endometriosis symptoms, seizures, PID, anemia, and fibroids [9]. The convenience and high efficacy rate (failure rate is 0.2%) of DMPA have made it increasingly popular with adolescents [8,38].

As noted, frequent spotting is common, particularly after the first injection, but periods typically become very light after the second injection, with many women going on to amenorrhea (50% to 60% at one year) [9,15]. Breakthrough bleeding on any progestin-only method should be evaluated to rule out pregnancy, infection, or cervical/uterine pathology. Once this is done, generally all that is needed is reassurance that bleeding is common during the first three to six months. COCs may be used for one cycle, or ibuprofen up to 600 mg three times daily may be taken for five days, to decrease bleeding [12]. The injection is an excellent option for women with poor compliance with daily, weekly, or even monthly methods. DMPA does not provide protection from STIs [9]. Upon discontinuing DMPA, there can be a significantly delayed return to fertility of up to 9 or 10 months [12].

There is much anecdotal evidence that the contraceptive injection causes weight gain, but this has not been proven in controlled studies [9]. Weight gain, when it occurs, can be up to 5 pounds at one year of use, and 16 pounds at five years of use. It is thought that the weight gain occurs due to a progesterone-induced increase in appetite, not a decrease in metabolism [12]. This modest increase in body weight does not appear to diminish the effectiveness of DMPA in preventing pregnancy [12,19].

Women who have migraines with aura while on DMPA, those with current deep vein thrombosis or pulmonary embolism, active liver disease, unexplained vaginal bleeding, or increased cardiovascular risk (e.g., hypertension with vascular disease, diabetes longer than 20 years, history of stroke, ischemic heart disease) are not good candidates for DMPA. Women with hormonally sensitive breast cancer should not use DMPA [9,23].

Long-term use may slightly improve depressed mood, and depression is not a contraindication [19]. In some women, however, progesterone-only methods may cause an increase in depression. This is a particular problem with the injected form, as it is not possible to "stop using" the contraceptive. It is advisable to use caution in women with a history of severe depression, including postpartum depression. It may be worth a trial of oral progesterone before prescribing the contraceptive injection in women with a history of depression [4].

Women on anticoagulation therapy can also use DMPA to suppress ovulation and prevent bleeding from the corpus luteum [19]. Women with seizure disorders may benefit from DMPA as a contraceptive, as it raises the seizure threshold [4,12,19]. Anticonvulsants have no effect on DMPA's effectiveness [4]. DMPA reduces the risk of painful sickle cell crisis by stabilizing red blood cell membranes, making sickle crises fewer and less intense; it can be a good contraceptive choice for women with this disease [12]. There is no evidence that the same precaution regarding antiretroviral use (decreased serum hormonal levels due to liver enzyme induction) applies to this contraceptive, as it does to the progesterone-only pills and implants [19,23].

The DMPA injection reduces the risk for endometrial hyperplasia and cancer. It is contraindicated in women with current or past breast cancer, and relatively contraindicated in women with a personal history of breast cancer (absolutely if hormone sensitive). It should be used with caution in women with active liver disease or liver tumors [9,23].

Another side effect that steers many women away from DMPA is the well-publicized loss of bone mineral density while on this medication. The large dose of progesterone suppresses estradiol production from the ovaries, impacting bone mineral density. There have been no cases of osteoporosis or bone fracture while on DMPA, and bone mineral density appears to return to the level of non-DMPA users within 12 to 30 months of discontinuing the medication, with adult former users having similar bone mineral density to those who never used the medication [12,39]. However, the FDA recommends no more than two years of use unless there is no other acceptable contraceptive method available [40]. The Society for Adolescent Medicine does not restrict use to two years [12]. Likewise, the ACOG does not impose a two-year limit on the use of DMPA, but it does recommend that women, particularly adolescents, exercise and take calcium and vitamin D; the ACOG does not recommend estrogen supplementation [9,39,40]. It also notes that implants and IUDs do not impact bone mineral density. The ACOG also notes that the bone loss seen with DMPA is similar to the temporary bone loss seen in pregnancy and breastfeeding (i.e., no long-term loss is observed) [39; 40]. The concern is that adolescents using DMPA are losing bone at a time of their life when they would typically be building bone. The loss of bone mineral density while on DMPA has unknown long-term effects on fracture risk later in life [12]. It is thought that bone density deficit is greater in women who started DMPA before 21 years of age and those who have used it for longer than 15 years [4]. At this time, dual-energy x-ray absorptiometry scanning is not recommended for otherwise healthy women on DMPA [40].

IUDs are extremely effective birth control, and they have one of the highest satisfaction and continuation rates among patients [37]. They are available in both hormonal and non-hormonal forms. They are considered LARCs, remarkable for their lack of user-dependence and their rapid return to fertility upon removal [37]. There are two IUDs currently available in the United States: the levonorgestrel IUD and the copper T380A. Both are considered appropriate for use in adolescents and nulliparous patients [37]. Neither has been shown to increase the rate of PID or tubal infertility. Both are acceptable for women with a history of ectopic pregnancy or PID [37]. Although the risk of a pregnancy occurring through IUD failure being ectopic is high, the absolute risk of pregnancy is so low that the absolute risk of ectopics is not increased statistically [37]. Expulsion, uterine perforation, and intrauterine pregnancy are also risks, though relatively low. Expulsion may be more common in adolescents and parous women [37].

Testing for STIs is not required before IUD insertion, although testing on the day of insertion is recommended in women who have not been screened for STIs, those at increased risk for STIs, and those with a personal history of STI [37]. A positive test may be treated without removing the IUD [37]. If there is a known STI or mucopurulent discharge at the time of insertion, the infection should be treated before inserting the IUD [37]. PID rates after insertion are the same as for the general population. The increased risk of PID attributed to IUDs appears to be associated with insertion; the risk is only elevated for the first 20 days after insertion. There is no relationship between IUD use and tubal infertility [12]. Routine prophylactic antibiotics at the time of insertion are not recommended [37]. If Actinomyces bacteria is noted on a Pap test for a woman with an IUD in place, treatment is not indicated unless the patient is symptomatic, in which case the IUD would be removed and antibiotics given [12]. All IUDs are contraindicated in women with congenital or acquired (e.g., due to fibroids) uterine cavity distortion [18].

The copper T380A is marketed under the brand name ParaGard in the United States. It is a T-shaped plastic device wrapped in copper wire along both arms and the long axis [37]. It is approved for 10 years of continuous use in the United States [18].

The device has several proposed mechanisms of action, including inhibition of ovum transportation speed, damage to the ovum itself, and impairment of sperm motility and viability [9; 18; 37]. It is also possible that the fertilized ovum can be damaged before implantation, although pre-fertilization effects are thought to be the primary mechanisms of action. The copper IUD can be used as effective emergency contraception before implantation occurs up to five days after unprotected intercourse [22]. As noted, the IUD can be used for 10 years and has a 1-year failure rate of 0.6 to 1.0 per 100 women and a 10-year failure rate of 1.9 per 100 women [4,8,37]. The failure rate of the copper IUD may be higher in younger women than older women [45].

The copper IUD can be inserted at any time in the menstrual cycle after confirming that the patient is not pregnant, except in cases of postpartum or postabortion sepsis [23]. A backup method of contraception is not needed. Expulsion rates are higher in adolescents and parous women and if the IUD is inserted immediately postpartum or after first-trimester abortions, but it may be considered based on patient-related factors [37]. There is no known effect of the copper IUD on breastfeeding. The insertion of an IUD should be delayed if a patient has a current uterine infection, but it does not need to be removed if an STI is diagnosed after insertion [9].

No hysteroscopic sterilization devices are available as of 2021 [45]. In 2002, the Essure device was approved in the United States for hysteroscopic sterilization [45]. However, based on reports of adverse events from patients and clinicians, the FDA held a postmarket panel meeting in 2015 to re-evaluate the benefits and risks [46,47]. Reported adverse events included implant perforation and migration, chronic pain, allergic reactions, irregular bleeding, and unintended pregnancy. Essure was removed from the market in 2018 [57].

Women who are exclusively breastfeeding will usually not ovulate for at least three months postpartum, although non- or partially breastfeeding women may ovulate as early as three weeks postpartum [12]. Women can have a false sense of security after giving birth and may not realize they can become pregnant. This can be a problem, as short inter-pregnancy intervals can lead to low birth weight and preterm deliveries [23].

Progesterone-only contraceptive methods, such as DMPA and progestin-only pills, may be used immediately postpartum as they do not increase coagulability or have effects on breast milk [12,19]. It is advised to wait four to six weeks before beginning COCs or other estrogen-containing methods due to the risk of clot from estrogen products and from the pregnancy/puerperium itself [19]. Some sources advise waiting six months if the woman is breastfeeding [12]. COCs have not been shown to impact infant development in well-nourished lactating women, although they may have effects on milk production and content [12,19].

It is advisable to wait four to six weeks for IUD insertion to avoid expulsion, although IUDs may be inserted sooner, even immediately after delivery, if the contraceptive benefits outweigh the risks [9; 37]. Delayed postpartum insertion (i.e., at the postpartum visit) is commonplace. If there has been a uterine infection with delivery or in the puerperium, it is advisable to wait three months before inserting an IUD [19,23]. Condoms may be used postpartum without a waiting period; other barrier methods should be delayed for six weeks [23].

Progesterone-only contraceptive methods, such as DMPA and progestin-only pills, may be used immediately postpartum as they do not increase coagulability or have effects on breast milk [12,19]. It is advised to wait four to six weeks before beginning COCs or other estrogen-containing methods due to the risk of clot from estrogen products and from the pregnancy/puerperium itself [19]. Some sources advise waiting six months if the woman is breastfeeding [12]. COCs have not been shown to impact infant development in well-nourished lactating women, although they may have effects on milk production and content [12,19].

Many of the contraceptive methods described in this educational activity can be used off-label as emergency contraception, including COCs, progesterone-only pills, and the copper IUD. More rarely, estrogen-only or antiprogestin methods (such as mifepristone) can be used [4,22,51,52]. The most common methods used in the United States have been progestin-only and COC methods; however, ulipristal acetate (UPA), a single-dose (30 mg) progesterone-receptor modulator, is a newer option and also the most effective oral emergency contraceptive [22,51,52]. UPA was approved for emergency contraception in 2010 and is only available by prescription.

As the UPA and progestin-only pills have fewer side effects (mainly less nausea and vomiting) and are more effective, they are recommended by ACOG [22]. All hormonal methods are capable of inhibiting ovulation or delaying ovulation, depending on the timing of the dose in relation to the menstrual cycle. It is also theorized that these medications can alter the endometrial lining, inhibit sperm transport, or interfere with the functioning of the corpus luteum. However, the data have not consistently supported these theories. Emergency contraception is ineffective after pregnancy is established; it is not an abortifacient, and it is not teratogenic [12,22].

The most common side effect is nausea and vomiting, particularly with combination methods [18,50]. An antiemetic given one hour before taking the combination dose can help to alleviate this side effect [50]. If vomiting occurs within two to three hours of emergency contraception ingestion, the dose should be repeated. Severe or persistent vomiting can be addressed with vaginal administration of the emergency contraception tablets, which does not impair their absorption. Irregular bleeding is also common, lasting from one day to one month after emergency contraception [18]. The next menstrual period is commonly either hastened or delayed by one week from the expected time. Less frequent side effects can include breast tenderness, abdominal pain, fatigue, headache, and dizziness [18]. There have never been any reports of deaths or severe complications from emergency contraception [22].

Emergency contraception has no effect on the risk of subsequent ectopic pregnancy [12,22]. It may also be used in any woman who has had a previous ectopic pregnancy and in women with other contraindications to combined oral contraceptives, such as migraines, cardiovascular disease, and liver disease. Emergency contraception may be used while breastfeeding [22].

A physical exam or pregnancy test is not required before dispensing emergency contraception [52]. A follow-up exam is also not required [22]. However, if menses have not occurred by one week after the expected time or within 21 days of emergency contraception use or if abdominal pain or bleeding are persistent, the patient should be evaluated [12,22].

When a woman presents to her healthcare provider for emergency contraception, it can be a good opportunity to discuss more reliable, long-term forms of contraception. It is also an opportunity to offer testing for STIs. It is important that any victim of sexual assault be offered emergency contraception; as noted, in some states this is required by law [12,63,65]. Long-term contraception should be initiated immediately after emergency contraception (in cases where a copper IUD was not used), as a woman can become pregnant later in the same cycle. Emergency contraception may be repeated more than once in the same cycle. Any non-barrier method of birth control may be initiated either immediately (with a barrier back-up method) or at the next menstrual period. Long-term methods, such as the progesterone injection, implant, or hormonal IUD, should be delayed until the next menstrual period confirms that the patient is not pregnant [22].