Contraceptive Choices

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[edit] Contraceptive Choices

Andrew M. Kaunitz

Half of all pregnancies in the United States are unintended, and about 1.4 million induced abortions are performed annually in U.S. women.^[1] Primary care physicians can play an important role in encouraging their patients to use effective methods of contraception. Unfortunately, no single method is ideal for all patients. Therefore physicians must consider such factors as overall effectiveness, patient compliance, and side effects as they help their patients make prudent contraceptive choices. This chapter reviews oral, injectable, implantable, intrauterine, barrier, and periodic abstinence contraception, focusing on approaches that help candidates select appropriate methods and management measures that maximize contraceptive efficacy and patient satisfaction.

Among U.S. women of reproductive age, approximately 64% used some form of contraception in 1995 (Fig. 38-1).^[2] The most popular method, used by 27.7% of women practicing contraception, was female sterilization. The next most common method was combination oral contraceptives (OCs), used by 26.9%. Approximately 21% used condoms for contraception, 3% used depot medroxyprogesterone acetate injections, 1.3% implants, and 0.8% intrauterine devices. Table 38-1 lists rates for first-year contraceptive failure and continuation.

Figure 38-1 Contraceptive use by U.S. women, ages 15-44. OCs, Oral contraceptives; IUD, intrauterine device. (Modified from Piccinino LJ, Mosher WD: Fam Plann Perspect 30;4, 1998.)

Table 38-1 First-year Contraceptive Failure (Unintended Pregnancy) and Continuation Rates in U.S. Women (%)

[edit] ORAL CONTRACEPTIVES

Since they first were marketed in the 1960s, the dose of sex steroids in combination OCs has dramatically declined. The highest-dose formulations now available contain 50 μg of ethinyl estradiol, and most currently prescribed OCs contain 30 or 35 μg. Formulations with 20 μg of estrogen represent the lowest-dose estrogen combination OCs currently available (Table 38-2). Monophasic OCs contain a constant dose of both estrogen and progestin in each of the 21 active tablets. Phasic OCs alter the progestin and/or estrogen dose among the 21 active tablets in an effort to minimize total steroid dose, as well as metabolic and side effects, while maintaining contraceptive efficacy.

Table 38-2 Oral Contraceptive Formulations Available in the United States

✢Generic versions also available.

†Indicated for treatment of acne as well as contraception.

‡Also includes 5 tablets containing 10 μg EE.

Most contraindications to combination OCs relate to their estrogen component (Box 38-1). Progestin-only OCs ("mini-pills," POPs) do not contain estrogen, with all the 28 tablets in each pack containing hormone. Because POPs contain progestins in even lower doses than combination OCs, failure rates with POPs are somewhat higher than with combination OCs.^[3] POPs, along with progestin-only injections and implants (see later sections), are well suited for use by lactating and older reproductive-age women with cardiovascular risk factors, two relatively less fertile groups for whom contraceptive doses of estrogen are contraindicated (Box 38-2). Contraceptive recommendations for women with medical problems are available.^[4]

[edit] Mechanism of Action.

Combination OCs prevent ovulation by inhibiting gonadotropin secretion. The progestin suppresses luteinizing hormone (LH) secretion, and the estrogen component suppresses follicle-stimulating hormone (FSH) secretion, preventing selection of a dominant follicle. The estrogen component also stabilizes the endometrium, thereby minimizing breakthrough bleeding. The progestin component also thickens the cervical mucus, minimizing entry of sperm into the endometrial cavity.

The substantially lower progestin doses of POPs blunt but do not totally eliminate midcycle LH peaks, with ovulation sometimes occurring in POP users. The effects of the POP on cervical mucus last about 20 hours, so meticulous pill taking is crucial to ensure high contraceptive efficacy. When a woman takes her POP more than 3 hours late, a backup method of contraception, such as condoms or a spermicide, should be used for the next 48 hours.

[edit] Initiation and Use.

When OCs are initiated on either the first day of menses or the first Sunday after menses starts, backup contraception is unnecessary. Associating pill taking with a daily ritual, such as tooth brushing, may enhance compliance. If one or two tablets are missed, the patient should take one tablet as soon as possible, then one tablet twice a day until all the missed tablets are taken. If three or more tablets have been missed, backup contraception should be used until the current pack is completed.

[edit] Side Effects.

As with all hormonal contraceptives, OC side effects represent the major cause of noncompliance and discontinuation. Because breast tenderness and nausea are common estrogen-related side effects, physicians may consider prescribing 20-μg estrogen OCs when these side effects persist for more than several months. Breakthrough bleeding occurs in up to one third of women during their first 3 months of OC use, subsequently becoming less common. Rates of breakthrough bleeding are higher among women using 20-μg estrogen than those using 30-or 35-μg formulations.^[5] The new onset of intermenstrual bleeding after 3 months of OC use should alert physicians to noniatrogenic causes, such as cervical infection or neoplasia. Once these conditions are excluded, oral estrogen (e.g., 1.25 mg of conjugated estrogen, esterified estrogen, or estropipate; 1 to 2 mg of estradiol) can be taken with each active OC tablet to minimize breakthrough bleeding caused by progestin-induced changes.

Amenorrhea caused by progestin-induced endometrial changes may result after long-term OC use, with resulting patient anxiety about possible pregnancy. Many physicians and users believe that OC use causes weight gain and headaches. A recent randomized placebo-controlled trial, however, found that rates of these "side effects" among women using an OC containing 35 μg of ethinyl estradiol combined with the new progestin norgestimate were nearly identical to those taking placebos.^[6]

[edit] Health Risks.

The estrogen component of combination OCs increases hepatic production of serum clotting factors, particularly factors I (fibrinogen), VII, and X. With use of OCs formulated with less than 50 μg of ethinyl estradiol, the risk of venous thromboembolism (VTE) is three to four times that of nonusers. Accordingly, women with a history of thromboembolism should not use combination OCs. To place this risk in perspective, pregnancy is associated with a VTE risk six times higher than in nonpregnant, non-OC-using women. Epidemiologic data do not suggest that VTE risk is lower with 20-μg estrogen formulations compared with 30 to 35 μg. Although initial data suggested that VTE risk was higher with OCs containing the newer progestin desogestrel, subsequent studies have not confirmed such differential risk.

Combination OC use, even long term, does not cause atherosclerosis. Likewise, the risk of myocardial infarction or stroke does not appear increased among healthy, nonsmoking women using OCs formulated with less than 50 μg of estrogen.^[5] Because OC use and smoking synergistically increase myocardial infarction risk, women age 35 and older who smoke should not use combination OCs.

Fears regarding breast cancer prevent many women from using OCs. A massive reanalysis has clarified associations between OC use and breast cancer. Ten or more years after discontinuing OCs, breast cancer risk is the same in ever-users and never-users of OCs. A modestly increased breast cancer risk noted in current and recent OC users may reflect increased screening in this population of women.^[5] Although OCs may increase risk of cervical adenocarcinoma, well-controlled studies have not found an increased risk of the more common squamous cell cervical cancer among OC users. Likewise, OC use has not been noted to impact the natural history of cervical human papillomavirus infection. As with all sexually active women, regular cytology screening is appropriate in women using hormonal contraception. A history of cervical intraepithelial neoplasia does not contraindicate OC use.

[edit] Concomitant Medications.

Certain anticonvulsants, as well as the antibiotic rifampin, may reduce the efficacy of OCs, particularly POPs (Box 38-3). The anticonvulsant valproic acid and the antibiotics doxycycline, tetracycline, metronidazole, and ampicillin do not appear to reduce OC efficacy.

[edit] Noncontraceptive Benefits and Therapeutic Uses.

Prevention of endometrial and ovarian cancer represents the most important noncontraceptive benefit of OC use. Because this protection persists for at least two decades after discontinuing pills, OC users in their late 30s and 40s can reduce their risk of being diagnosed with these malignancies during those decades of life when they would otherwise experience their highest lifetime risk of these cancers (Boxes 38-4 and 38-5).^[5]

[edit] Use in Perimenopausal Women.

Use of combination OCs is safe in healthy nonsmoking women of any reproductive age. U.S. women in their 40s are increasingly taking advantage of the effective contraceptive protection offered by OCs. In addition, perimenopausal women benefit from the regularization of menses, relief from vasomotor symptoms, and positive impact on bone mineral density offered by combination OCs. Because gonadotropin levels fluctuate in perimenopausal women, assessment of FSH levels to determine when older OC users no longer need contraception is expensive and may be misleading. A preferable approach is to continue having healthy nonsmoking women take combination OCs into their middle 50s. At this time, the likelihood of ovulation is low; hormonal replacement therapy can be initiated in such women on an individualized basis.

[edit] POSTCOITAL OR EMERGENCY CONTRACEPTION

About half the unintended pregnancies in the United States occur in women not using contraception. Emergency contraception (EC), commonly referred to as the "morning- after pill" or postcoital contraception, is a method of preventing pregnancy after unprotected sexual intercourse. The best studied and most commonly used EC method in the United States is the Yuzpe regimen, consisting of 0.1 mg of ethinyl estradiol and 1.0 mg of DL-norgestrel (two Ovral tablets; see Table 38-2) taken within 72 hours of unprotected intercourse, with a second dose taken 12 hours later. Recent U.S. Food and Drug Administration (FDA) approval of an EC kit containing a urine pregnancy test and four tablets (Preven) facilitates use of the Yuzpe regimen. The most common side effect of EC is nausea and vomiting; an antiemetic taken 1 hour before each dose may reduce this side effect. Use of POPs can provide effective EC without estrogen-induced nausea; this approach utilizes one Plan B tablet or 20 75-μg norgestrel tablets (Ovrette), with this dose then repeated in 12 hours.

[edit] INJECTABLE CONTRACEPTIVES

Depot medroxyprogesterone acetate (DMPA) is marketed in the United States as Depo-Provera, a 150-mg solution of aqueous microcrystals administered by deep intramuscular injection every 3 months.^[7] A new drug application has been filed with the FDA for a monthly contraceptive injection combining 25 mg of medroxyprogesterone acetate with 5 mg of estradiol cypionate (Lunelle).^[8]

[edit] Mechanism of Action.

DMPA provides highly effective contraception by blocking the LH surge and preventing ovulation.

[edit] Initiation and Use.

When DMPA is initiated within 5 days of the onset of menses, backup contraception is unnecessary. After initial or subsequent injections, ovulation does not occur for at least 14 weeks, allowing a 2-week grace period when 3-month injection intervals are followed. For women more than 2 weeks late for their reinjection, pregnancy should be ruled out before reinjection and backup contraception used for 1 week subsequently.^[7] Depo-Provera package labeling states that pregnancy should be excluded in women more than 1 week late for reinjection. Fortunately, contraceptive doses of DMPA inadvertently administered during pregnancy do not appear to result in increased risk of congenital anomalies.

[edit] Side Effects.

Menstrual changes occur in all women using DMPA. Episodes of unpredictable, irregular bleeding and spotting lasting 7 or more days typically occur in the first months of use. With increasing duration of use, frequency and duration of these episodes decrease, and amenorrhea becomes common. After four injections of DMPA, half of women report amenorrhea, with this percentage increasing to more than three fourths with longer use. Based on unrealistic expectations of immediate amenorrhea, users may prematurely discontinue their contraceptive injections after experiencing unpredictable spotting and bleeding. Candid counseling before the first injection, as well as supportive follow-up measures, can enhance injectable contraceptive continuation. If reassurance is not sufficient to encourage women experiencing menstrual changes to continue DMPA, persistent, irregular bleeding can be treated with continuous daily oral estrogen supplementation (as described earlier for OC breakthrough bleeding). After the discontinuation of supplemental estrogen, however, the bleeding may return. Possible side effects from DMPA include bloating, alopecia, and reduced libido. Although anecdotal observations had suggested that DMPA use might cause weight gain and depressive symptoms, recently published well-controlled studies have not confirmed this.

[edit] Return to Fertility.

Return to fertility can be delayed after discontinuing DMPA. Within 10 months of the last injection, half of women who have discontinued DMPA to become pregnant will have conceived. Fertility does not return in some women for up to 18 months after the last injection, however, underscoring that DMPA is not an appropriate choice for women who may want to conceive in the next 1 or 2 years.

[edit] Health Risks.

Use of DMPA is associated with modest suppression of ovarian estradiol production. Although earlier studies suggested that users experience a reversible decline in bone mineral density, larger recent studies have not consistently confirmed this concern. As in all reproductive-age women, appropriate calcium intake should be encouraged. Because adolescent DMPA users and women who use DMPA for more than 5 years continuously may be at increased risk for low bone mineral density, estrogen supplementation (i.e., conjugated estrogen 1.25 mg daily or its equivalent) can be used along with DMPA. Levels of high-density lipoproteins have been found to be lower in DMPA users. World Health Organization studies have found that DMPA does not affect cervical or ovarian cancer risk but greatly reduces endometrial cancer risk. DMPA's impact on breast cancer risk appears similar to that of OCs.^[7]

[edit] Noncontraceptive Benefits and Therapeutic Uses.

Boxes 38-6 and 38-7 list noncontraceptive benefits and therapeutic uses of DMPA. Concomitant use of liver enzyme–inducing medications has not been demonstrated to impair DMPA effectiveness (see Box 38-3). Since DMPA has intrinsic anticonvulsant properties, some believe it should be the contraceptive of choice for women with seizure disorders.

[edit] CONTRACEPTIVE IMPLANTS

The Norplant subdermal contraceptive system consists of six 34×2.4–mm Silastic tubes, each containing 36 mg of crystalline levonorgestrel. The six implants release a total of 85 μg/day initially, with the levels dropping to 30 μg/day by the fifth year of use. The 5-year cumulative failure rate is 1.3 per 100 users, comparable to the failure rate of tubal sterilization.^[9][10] Failure rates slowly rise as the levonorgestrel release rates gradually decline. Because failure rates rise above 2 per 100 woman-years in the sixth year of use, implants should be replaced after 5 years. The risk of congenital anomalies does not appear to be increased among offspring born to women with implants who have conceived.

[edit] Mechanism of Action.

Circulating progestin levels are sufficient to prevent ovulation in most women using implants. However, approximately one third of implant users do experience cyclic luteal activity in the first year. This luteal activity becomes more frequent in subsequent years and is associated with regular withdrawal bleeding episodes. In these ovulatory implant users, fertilization is prevented by progestin-induced luteal insufficiency, impaired oocyte maturation, and progestin-induced cervical mucus. Implant users with cyclic menses are at higher risk of pregnancy and should be counseled about the importance of pregnancy testing if their regular menses abruptly cease.

Medications that induce hepatic enzymes can decrease implant efficacy (see Box 38-3). Some physicians have successfully placed two sets of implants (12 total implants) in women taking concomitant hepatic enzyme inducers. A two-implant levonorgestrel system that provides at least 3 years of contraception has been FDA approved but is not currently marketed in the United States.

[edit] Initiation, Use, and Return to Fertility.

Insertion of the implants within 7 days of the onset of menses avoids the need for backup contraception. Insertion and removal of implants are minor office procedures performed under local anesthesia. Removal takes longer and is associated with more discomfort than insertion. Appropriate insertion technique facilitates removal. Because serum progestin levels fall rapidly after removal, fertility returns within days or weeks of removal. This observation underscores that women having their implants removed need to initiate an alternate method of contraception immediately if they want to avoid conceiving.

[edit] Side Effects.

Irregular bleeding is the most common side effect leading to implant discontinuation and can be treated with estrogen supplementation (e.g., DMPA). Headache (nonmigraine), mood changes, and weight gain are the most common nonmenstrual side effects leading to implant discontinuation in U.S. women.^[10] Some women using implants have reported hair loss, a side effect that appears to diminish during implant use.

[edit] Health Risks.

No epidemiologic data have assessed risk of reproductive tract cancers in implant users. Functional ovarian cysts arising from persistent dominant follicles develop in some implant users but rarely require surgical intervention.

[edit] INTRAUTERINE DEVICES

Intrauterine devices (IUDs) offer convenient, highly effective, and safe contraception. Low use of IUDs among U.S. women likely reflects myths that IUDs act as abortifacients and cause pelvic inflammatory disease (PID), infertility, and ectopic pregnancies. By educating women and dispelling myths, primary care physicians can encourage appropriate candidates to take advantage of this underused contraceptive.^[11]

The two IUDs currently available in the United States are the Copper T 380A (Paragard) and the progesterone-releasing IUD (Progestasert). Paragard is a polyethylene device covered with 380 mm² of copper. Two white monofilament threads are tied to the device's bulbous stem. Progestasert is a T-shaped ethylene/vinyl acetate copolymer device whose stem is filled with 38 mg of progesterone, released at a rate of 65 μg per day. Two blue-black monofilament strings are attached to the stem base. Barium sulfate is incorporated into the frame of these IUDs, making them radiopaque.

[edit] Mechanism of Action.

IUDs prevent fertilization by creating a sterile, inflammatory foreign body response in the endometrial cavity that is hostile to sperm. Copper causes local prostaglandin production and inhibits endometrial enzymes, intensifying the spermicidal impact of the copper IUDs. Paragard is approved for 10 years of use, with first-year failure rates of 0.5 to 0.8 per 100 woman-years and a cumulative 10-year failure rate of 2.1 per 100 woman-years, comparable to tubal sterilization.^[9] Recent data suggest this IUD remains effective for at least 12 years.

Progestasert not only inhibits sperm survival but also may prevent implantation by creating an atrophic decidualized endometrium. The progesterone-releasing IUD also thickens the cervical mucus, preventing sperm entry into the endometrium. Approved for 1 year of use, the first-year failure rate is a reported 2 per 100 woman-years.^[3]

[edit] Initiation and Use.

Many physicians believe that IUDs are best inserted during menses, when insertion-related bleeding is masked, discomfort may be minimized by increased cervical dilation, and pregnancy is ruled out. IUDs, however, may be inserted any time during the cycle as long as pregnancy can be reliably excluded. Although uterine perforation can occur during insertion, this complication rarely occurs with the copper or progesterone-releasing IUDs. Skilled physicians who perform a careful preinsertion bimanual examination have perforation rates of approximately one per 1000 insertions. Appropriate sterile technique and patient selection (i.e., avoiding insertion in patients with current genital infections or at increased risk for sexually transmitted diseases) preclude the necessity for prophylactic antibiotics. Expulsion rates are approximately 5% in the first year of copper IUD use. Vaginal discharge, cramping, a lengthening string, and plastic protruding from the cervix suggest partial expulsion, and barrier backup contraception should be used until the patient can be evaluated. Partially expelled IUDs should be removed. A new device can be inserted after infection and pregnancy are excluded.

[edit] Side Effects.

Copper IUDs increase both menstrual flow and cramping. Careful screening of candidates to avoid insertion in women with preexisting menorrhagia or dysmenorrhea will reduce patient discontinuation resulting from these problems. Use of nonsteroidal antiinflammatory drugs (NSAIDs) is appropriate for women using copper IUDs and experiencing dysmenorrhea. Because the progesterone-releasing IUD reduces menstrual flow and cramps, women with underlying heavy flow or dysmenorrhea may be good candidates for or may even benefit from its use.

[edit] Health Risks.

In contrast with barrier and hormonal contraception, IUDs do not prevent sexually transmitted diseases (STDs) or PID. Selection of mutually monogamous candidates with no evidence of genital tract infection and use of good insertion technique should result in little if any increased risk of pelvic infection after IUD insertion. Because copper IUDs reduce the overall risk of ectopic pregnancy, a history of ectopic pregnancy does not contraindicate their use. Conditions no longer considered contraindications to IUD use include nulliparity, diabetes mellitus, valvular heart disease, treated cervical dysplasia, anovulatory cycles, lactation, and corticosteroid use without immunocompromise.

Uncomplicated vaginitis or cervicitis encountered in IUD users should be treated as in any other patient. Simple endometritis can be treated with doxycycline and metronidazole (or ampicillin/clavulanate) for 14 days without IUD removal if the patient responds appropriately. Although no controlled study has addressed this issue, many authorities believe PID requires removal of the IUD after initiation of antibiotics. Actinomyces has been found on Papanicolaou smears in up to one third of women with plastic IUDs and in almost 1% of copper IUD users with long duration of use. In women with Actinomyces infection and either uterine tenderness or an associated pelvic mass, appropriate treatment includes removal of the device and oral penicillin for 1 month.

Although the copper-T IUD does not increase ectopic pregnancy risk, when contraceptive failures occur in IUD users, a high percentage of such pregnancies are ectopic. Accordingly, physicians diagnosing pregnancy in an IUD user should promptly arrange sonography to determine the implantation site. The risk of spontaneous abortion is increased if an IUD remains in place with an intrauterine pregnancy. If the string is visible, the IUD should be gently removed, regardless of the woman's pregnancy intentions. Once the IUD is removed, the increased risk of abortion resolves. If the string is not visible, some experts recommend sonographically guided removal by a physician skilled in such procedures. If the IUD cannot be retrieved, the risk for congenital anomalies has not been shown to be increased, but the risk of preterm labor or intrauterine infection is greater.

[edit] BARRIER AND SPERMICIDAL METHODS

Paralleling increased awareness of human immunodeficiency virus (HIV) infection and other STDs, the use of male condoms among U.S. couples has become more common. Barrier methods can be relatively effective when used consistently and correctly. Younger age, lower socioeconomic class, and less education correlate with higher barrier and spermicide failure rates. Vaginal foams, jellies, suppositories, creams, and films containing the spermicidal detergent nonoxynol 9 kill or immobilize sperm on contact. Combining these spermicidal methods with barriers may increase contraceptive efficacy, but many couples perceive spermicides as messy or having an unpleasant flavor.

[edit] Initiation and Use.

Diaphragms and spermicides used alone require proper placement before penile-vaginal contact, with additional spermicide placed with each subsequent sex act. Diaphragms should be left in place for at least 6 hours after sexual relations. Arcing-spring diaphragms are used most often and can be used by women with pelvic relaxation or an anterior cervix associated with a posterior uterus. Flat-spring diaphragms are also available.

In contrast with diaphragms, cavity rim cervical caps have the advantages of (1) allowing longer use, up to 36 hours at a time; (2) not requiring concomitant spermicide use with each coitus; and (3) maintaining appropriate placement in women with pelvic relaxation by means of the suction created. Failure rates with the cap are higher in parous than nulliparous women, with rates as high as 20% reported among parous women consistently using this device.

Diaphragms and cervical caps are available in different sizes, must be professionally fitted, and require users knowledgeable about and comfortable manipulating their genital anatomy. Male and female condoms can be used effectively without spermicides.

[edit] Side Effects.

Vaginal pain or ulceration is rare with a properly fitted diaphragm or cervical cap. Diaphragm users should be reevaluated for correct fit annually, after any 4.5-kg (10-pound) or greater weight change, after an abortion, and postpartum.

[edit] Health Risks.

Urinary tract infections are approximately twice as common among women using diaphragms as among those using OCs. Some individuals are allergic to latex condoms, diaphragms, or cervical caps.

[edit] Noncontraceptive Benefits and Therapeutic Uses.

Use of barriers and spermicides reduces the transmission of bacterial and viral STDs.

[edit] PERIODIC ABSTINENCE

The rhythm (calendar) method, cervical mucus method, and symptothermal method are approaches to contraception that rely on observation of signs and symptoms of the "fertile" period during the menstrual cycle. Accordingly, women with irregular menses, vaginitis, or cervicitis are not appropriate candidates for use of periodic abstinence. Periodic abstinence is the only method of contraception allowed by some religions. The need to abstain from sex for many days each menstrual cycle and the high failure rate limit this approach to fertility regulation.

[edit] SUMMARY

Hormonal and intrauterine contraception offer women safe, effective, and reversible contraception. Use of oral and injectable contraceptives also confers a number of important noncontraceptive benefits. Barrier and spermicidal methods are readily accessible and offer women protection against unintended pregnancy and STDs. By individualizing counseling and recommendations based on relevant behavioral and medical considerations, primary care physicians can maximize their patients' success with contraceptives.

[edit] REFERENCES