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Contraception and Birth Control

Although 90% of women who are at risk for pregnancy use some form of birth control, nearly 50% of all pregnancies (excluding miscarriages) and 31% of all births in the United States are unintended. "Unintended pregnancy" is defined as pregnancy in a woman who wanted no children at the time of conception contraception, birth control, intrauterine device, depoprovera, norplant. At a minimum, an unintended pregnancy represents a missed opportunity to achieve the benefits of preconceptional care. The category of "unintended pregnancies" includes not only pregnancies that

Abbreviation: IUD indicates intrauterine device.

Permanent Sterilization

Nearly one of every four women in the United States relies on permanent sterilization of herself or her partner. Worldwide, sterilization is the most common form of contraception. Longer-term studies of the 1 O-year cumulative failure rates for permanent sterilization showed that postpartum partial salpingectomy is more effective than

Emergency Contraception

Women exposed to sperm by unprotected intercourse, condom breakage, or other contraceptive mishaps are candidates for emergency contraception with oral contraceptives. After nearly three decades of clinical experience with emergency contraception in this country, the Food and Drug Administration (FDA) now has approved a product for emergency contraception with oral contraceptives. An emergency contraceptive kit includes patient instructions, a urine pregnancy test, and four combination contraceptive pills with estrogen and progestin. The kit has advantages over previous pill combinations because it may be prescribed in advance of need, it includes instructions specific to

Oral Contraceptives

Combination oral contraceptives contain both synthetic estrogen and progestin. Ethinyl estradiol is the estrogen used in all of the sub-50-:g formulations and also in many of the 50-:g pills. Its 3-methyl ester, mestranol, is used in a few of the 50-:g pills; mestranol must be hepatically converted to ethinyl estradiol to 

All progestins in oral contraceptives are 19-nortestosterone androgen derivatives. Seven different pro-gestins are available in the United States; they vary in progestational and residual androgenic activities. The first group of

Formulations

Combination oral contraceptives containing both a synthetic estrogen and progestin are taken daily, typically in a pattern of 3 weeks of active pills followed by a -week steroid-free period. Combination oral contraceptives are

Side Effects

Many of the adverse effects of oral contraceptive use reported in the older literature were found subsequently to be dose related. As a result, the incidence of side effects has diminished dramatically as the hormonal content of the pill has plummeted. In the 1960s, the pill had 150 ug of mestranol and 10 mg of progestin, whereas modem low-dose formulations have 20-35 ug of estrogen and 1 mg or less of progestin. Side effects reported to occur with oral

Reproductive Tract Effects

The cyclic administration of pharmacologic doses of synthetic sex hormones directly affects the endometrium and most frequently produces predictable, coordinated withdrawal bleeding. Endometrial shedding induced by oral contraceptives prevents many of the long-term sequelae of unopposed estrogen, which is particularly important to women with anovulatory cycles. Users of oral contraceptives have a decreased risk of endometrial cancer (relative

The myometrium is also affected by oral contraceptives. One study showed that use of combination oral contraceptives for at least 4 years reduces the risk of formation of leiomyomas by at least 40%. In women with preexisting fibroids followed for 1 year, oral contraceptive pill users had no difference in the growth for their

Oral contraceptive use significantly reduces a woman's risk of developing ovarian epithelial carcinoma. The relative risk of ovarian cancer in short-term oral contraceptive users is 0.6 and drops to 0.2 after 10 years of oral contraceptive use. Studies show that this protection persists 15 years beyond the time the woman takes her

Effects on Breast

The association between oral contraceptives and breast cancer is at best transient. Meta-analysis of 54 studies involving 53,297 cases of breast cancer and nearly twice as many controls found that the impact of oral contraceptives was analogous to the effect of pregnancy. Overall, the relative risk of breast cancer in ever-users is slightly elevated (relative risk = 1.07; confidence interval = 1.03, 1.10), but the increased risk is apparently confined to current and recent users (those with less than 10 years since last use). Analyzing the data by age, it has

Cardiovascular Effects

Early studies involving high-dose oral contraceptives used in women regardless of their cardiovascular risk status seemed to indicate that high-dose oral contraceptives increased the risk for myocardial infarction and stroke. More recent studies involving lower-dose oral contraceptives have failed to find any increased risk of myocardial infarction in nonsmokers.

Several lines of evidence are available demonstrating that oral contraceptive users are not at increased risk for atherosclerotic heart disease. Animal studies demonstrate that estrogen in oral contraceptives actually decreases the size of atherosclerotic plaques. In humans, past users have no higher rates of myocardial infarction than nonusers, and

Effects on Liver and Gallbladder

Sex steroids, especially estrogen, increase hepatic protein synthesis. Increased production of sex hormone-binding globulin can be very helpful in reducing circulating free androgens in women who have acne or hirsutism. Renin substrate production increases, which may cause blood pressure elevation in women who are sensitive to

Myths and Misinformation

A recent American Medical Association survey found that 96% of American women believe they are knowledgeable or very knowledgeable about contraception. However, most of these same women were misinformed about pill use. Even more disturbing are the results of surveys conducted by the American College of Obstetricians and Gynecologists showing that nearly two thirds of Americans believe that oral contraceptives are at least as hazardous to a woman's health as pregnancy. Cancer is their primary concern. More than 40% of adults significantly

Special Applications

Oral contraceptives are an excellent contraceptive choice for adolescents at risk for pregnancy. There is no evidence that early use interferes with maturation of the hypothalamic-pituitary-ovarian axis or that it will induce premature closure of the epiphyseal plates. Pills provide many important benefits that are important to young women, including decreased acne, menstrual regulation, and decreased dysmenorrhea. Early use facilitates long-term use, which can lead to significant health benefits in reduction of endometrial and ovarian carcinoma and reduced risks for ectopic

Intrauterine Contraceptive Devices

Types

Two different types of intrauterine devices (IUDs) are available in the United States. One is a T-shaped plastic IUD with copper wire wrapped around the stem and a solid copper sleeve on each of its arms. Approved for 10 years of use, its first-year typical failure rate is 0.7% and its cumulative 10-year failure rate is 2.1%. Recent studies show that it is effective for at least 12 years. These rates compare favorably to the failure rate of sterilization, particularly in unprotected intercourse.

Effects and Complications

Both types of IUDs affect menstruation. The copper 1UD typically increases menstrual blood loss about 35%, but this loss can be reduced by nonsteroidal antiinflammatory drugs administered at the onset of menses and continued at least through the heavy-flow days. The progesterone IUD induces endometrial atrophy and may cause irregular spotting, oligomenorrhea, or

The complications related to IUD use generally occur near the time of insertion. The incidence of uterine perforation is 1 in 1,000-2,000 insertions and is most strongly influenced by the experience of the inserter. Expulsion or partial expulsion occurs in approximately 5.5% of IUD users during the first year. Avoiding insertion during menses can

Infections related to IUD use are relatively rare but are concentrated in the immediate postinsertion period, when the rate is about 1 per 1,000 insertions. Cultures obtained from hysterectomy specimens of IUD users demonstrated that the endometrial cavity is temporarily colonized immediately after insertion but becomes sterile before the

The workup of missing strings is straightforward. Once pregnancy has been ruled out, the location of the IUD can be determined by probing the endocervical canal with a cytology brush or uterine sound. Search of the intrauterine cavity is best done with alligator forceps. Imaging studies, especially with ultrasonography, can locate the IUD. Hysteroscopy is usually reserved for embedded devices. If the woman is pregnant, ultrasonography should be

Long-Acting Progestin Methods

Both implants and depot medroxyprogesterone acetate (DMPA) injections are intermediate- to long-term progestin-only contraceptive methods that are highly effective, convenient, and estrogen free. There are few contraindications to their use; even many women with serious medical problems are candidates for these methods.

Contraceptive Implants

The currently available implant system consists of six silicone rubber capsules, each filled with 36 mg of levonorgestrel. The capsules are placed in a superficial plane in the subcutaneous tissue beneath the skin of the medial aspect of a woman's upper arm. Levonorgestrel is slowly released from the capsules and provides rapidly reversible contraception for up to 5 years. Insertion is recommended within the first 5 days of the menstrual cycle; if it occurs at other times in the cycle, a back-up method should be used for 5 days. The insertion procedure is relatively

The levonorgestrel implants have several mechanisms of action. Initially, when levonorgestrel levels are high, ovulation is suppressed in about 80% of women. Over time, ovulatory cycles resume and the system relies on thick, impenetrable cervical mucus for its contraceptive efficacy. Endometrial atrophy may play a 

Once the capsules are removed, levonorgestrel levels fall rapidly. Within 3 days, they are subtherapeutic. Ovulation resumes in 2-4 weeks, and fertility is promptly restored. If a woman desires a second set of implants, the implants can be inserted through the same incision in the same general area that the first set occupied. If the removal has been complicated by swelling or hematoma or was unduly prolonged, the new implants can be placed in a different site.

New techniques have been developed to facilitate both the insertion and removal procedures. Buffering the anesthetic with sodium bicarbonate in a 5:1 ratio reduces the discomfort associated with its infusion. Injecting the anesthetic in an arc above the area to be manipulated creates a field of anesthetized tissue that does not have any hematomas to

Depot Medroxyprogesterone Acetate

Depot medroxyprogesterone acetate is an aqueous suspension of microcrystals of progestin given by intramuscular injection every 11-13 weeks. The approved contraceptive formulation has a concentration of 150 mg/mL; a standard 1-cc dose is administered regardless of patient weight. Immediately after injection, the site may be tamponaded, but

Barrier Methods

Barrier methods are coitally related and require timely and consistent user participation. As such, they have higher typical failure rates than the previously discussed methods. However, they are easily reversible, cause few side effects, and have low initial costs. Many are available without physician interaction. They offer some measure of STD risk reduction.

Male Condoms

Male condoms have typical failure rates of 10-12%, but those rates are as high as 20% when condoms are used by teenagers. Perfect-use failure rates are estimated to be 2%. Condoms are available in three materials: latex,

Female Barrier Methods

The diaphragm, cervical cap, female condom, and spermicidal agents are the currently available female barrier methods. For nulliparous women, the diaphragm and cervical cap have similar typical failure rates (16-18%). Multiparous cervical cap users may have higher failure rates, underscoring the need for careful professional fitting.

Natural Family Planning and Fertility Awareness Methods

Natural family planning (periodic abstinence during the fertile interval in a woman's menstrual cycle) and fertility

Other Methods

Abstinence is used by 200 million women worldwide and, if practiced, is absolutely effective. Lactational amenorrhea, if accompanied by exclusive breastfeeding on demand (>90% of infant nutrition from breastfeeding) and no other sucking experience for the infant, has a 2% failure rate for the first 6 months postpartum. Withdrawal, or