Approach to Fertility Control

Kerri Palamarsa

Despite almost all women reporting contraception use at least once during their reproductive years, roughly 50% of all pregnancies in the United States are unintended. Of those, 50% are due to contraception failure from incorrect use, inconsistent use, or method failure, and 50% are due to nonuse of contraception. Half of unintended pregnancies will end in abortion. The prevalence of unintended pregnancies varies with the woman’s age, race, level of education achieved, and income. It accounts for 80% of teenage pregnancies and 40% among women in their perimenopausal years and is higher in blacks and women whose income is below the poverty line. These high rates belie the general understanding that great progress has been made in contraceptive technology and the current reported use of 89% of reproductive-aged women.

The primary care clinician should be knowledgeable about available fertility control methods and the factors that influence their effectiveness, including sociocultural factors. The goal is to help the patient or couple desiring fertility control to intelligently select the approach that suits them best, one that is most consistent with their values, lifestyle, and preferences.

FERTILITY CONTROL: OVERVIEW

Fertility control can be divided into natural, hormonal, and nonhormonal contraceptives and surgical methods (see Table 119-1). The ideal fertility control approach would be perfectly safe, highly effective, inexpensive, acceptable, and available. No such option exists.

Measures of Effectiveness

The effectiveness of individual fertility control methods can be expressed in several ways:

Theoretical effectiveness refers to the ability of the medication, device, or procedure to prevent pregnancy if applied under ideal conditions (known as perfect use).
Use effectiveness combines theoretical effectiveness with inherent patient-related lapses in application.
Extended-use effectiveness adds the dimension of time and is often expressed as the number of unintended pregnancies per 100 women per year (known as typical use).

Despite variation in effectiveness, use of a fertility control method is better than no method at all, as it is estimated that 85% of women age 15 to 44 will become pregnant within 1 year of regular unprotected intercourse.

NATURAL METHODS (1, 2 and 3)

Natural methods of birth control depend on the woman being able to develop an approach to fertility awareness that she can understand and use consistently. Faithfully practiced rhythm, with daily basal body temperature recording to predict ovulation and abstinence dates, usually results in one pregnancy every 2 years or at least one more child than planned by the couple by their late 30s. Use of menstrual dates to plan abstinence is less effective. Rhythm controlled by following the cervical mucus cycle is confounded by infections, dietary changes, douching habits, oral medications, the patient’s understanding of her anatomy, and the availability of testing materials. One needs to understand reproductive anatomy and physiology and have the privacy to conduct such tests. The amenorrhea of lactation is useful in providing an infertile period after childbirth, but the duration of ovarian inactivity in an individual is hard to predict or follow. Withdrawal is probably the most commonly used yet least recommended natural contraceptive technique. Unfortunately, even when withdrawal before ejaculation is achieved, pregnancy can result from discharge of semen before ejaculation or subsequent sperm migration from the perineum. Failure rates as high as 27% have been reported.

BARRIER CONTRACEPTIVES (4, 5, 6 and 7)

Condoms

Condoms have moderate extended-use effectiveness. This method is 85% effective with typical use and 95% effective with perfect use. The condom is inexpensive, widely available, and the only barrier method that protects against sexually transmitted infections. It requires no medical intervention or prescription. Newer, high-quality, thin condoms are affordable and mitigate concerns about the loss of sensation. Failure by means of rupture occurs rarely but is easily recognized, thereby providing the opportunity for emergency contraception as a backup (see Emergency Contraception). Most condoms are made of latex. Polyurethane condoms have been approved for people with latex sensitivity, but breakage rates are higher, and overall contraceptive effectiveness is not as well documented. The condom has protective effects against infectious agents such as HIV, Chlamydia, gonococci, herpes simplex virus, and human papillomavirus (HPV).

Female condoms are lubricated polyurethane pouches that line the vagina. One outer ring lies outside the body, and a smaller inner ring is pushed up toward the cervix to hold the condom in place. It gives a woman an additional choice and freedom to protect herself from sexually transmitted infections and pregnancy. Because it is made from polyurethane, the female condom can be used by latex-allergic individuals. Female condoms appear to have failure rates similar to those of the male condom. Unfortunately, they cost about three times as much as the male condom.

Diaphragms

Diaphragms are synthetic latex barriers mounted on covered rims that deny access of the penis and its ejaculate to the anterior vaginal wall and cervical os. A physician, nurse, or trained technician must fit the diaphragm to the individual woman. Women who are comfortable exploring their vagina and taking the time to prepare prior to intercourse are best suited for diaphragm use. The largest diaphragm should be selected that will cover the cervix and anterior vagina from the symphysis pubis to the posterior fornix, while not causing discomfort. It should not stretch the rest of the vagina or put undue pressure on the urethra. Some women cannot be fitted adequately with a diaphragm for anatomic reasons. Only significant weight changes of 25% or more of body weight require diaphragm refitting. Refitting should be performed 6 weeks or more postpartum as well.

TABLE 119-1 Available Fertility Control Methods

Natural	Hormonal	Nonhormonal	Surgical
Rhythm method	Combined oral contraceptives	Condoms (male and female)	Tubal ligation
Fertility-based awareness	Vaginal ring	Vaginal sponge	Vasectomy
Withdrawal	Progestin-only pill	Lea Shield
Lactation amenorrhea method	Injectable progestin	Diaphragm
	Subdermal implants	Cervical cap
	Progestin-containing IUD	Copper IUD
	Transdermal patch
	Emergency contraception pill

The cost of the diaphragm is reasonable. When used properly, diaphragms with a small amount of spermicidal cream or jelly are up to 95% effective. This facilitates insertion but need not be used in the large amounts recommended by the manufacturers because it is unpleasantly messy. Additional spermicidal cream needs to be applied intravaginally for repeated intercourse. The diaphragm is worn for 6 hours after the last coital event because this is the length of time during which sperm motility persists. It may be worn while the patient is swimming or during menstruation.

The two most frequent complaints regarding the diaphragm are latex allergy and increased frequency of urinary tract infections. The Wide-Seal diaphragm has a wider band around the rim, which puts less direct pressure on the urethra and may reduce the frequency of urinary tract infections. The woman who has experienced infections should also be advised to void after intercourse and use adequate lubrication.

Cervical Caps

Cervical caps fit snugly over the cervix and are slightly more difficult to insert and remove. Their use requires physician or nurse instruction, and they are more costly than diaphragms. Four sizes are manufactured, and some women cannot be fit. For these reasons, they are less popular than the diaphragm. For women who have recurrent urinary tract infections, however, they are particularly useful because they do not press on the urethra. In addition, they can be worn for 48 hours, during which time intercourse may be repeated without the addition of spermicidal cream. There is evidence of a modest increase in the incidence of abnormal Papanicolaou (Pap) tests; therefore, it is recommended that a Pap test be performed 3 months after initiating the use of the cap. If the Pap smear is normal, then the woman can proceed with routine screening Pap tests.

The Lea Shield and Contraceptive Sponge

Similar in some aspects to both the diaphragm and cervical cap is the Lea Shield. It is a cup-shaped silicone device inserted before intercourse like a tampon, along with a spermicide, and is left in place for at least 8 and as many as 48 hours after. Advantages are that it is washable, is reusable for 6 months, and is available without a prescription and one size fits all.

The contraceptive sponge is impregnated with nonoxynol-9 spermicide and is inserted deep into the vagina after moistening with water. Its manufacture was interrupted in 1995 because of concerns regarding the risk of toxic shock syndrome, but it again became available in 2005 as the Today sponge.

Spermicidal Creams, Jellies, and Foams

Spermicidal creams, jellies, and foams may have a high theoretical effectiveness, but they have lesser use effectiveness and do not protect against sexually transmitted infections. Most are readily available in supermarkets and drugstores and contain nonoxynol-9 as the spermicidal agent. The physical nature of the creams and jellies and difficulty in their application often result in inadequately smearing the cervical os, so that sperm invasion is not prevented. Both men and women complain of the dehydrating effect of spermicidal agents and may report burning sensations.

Foams have better physical properties, allowing more adequate smearing of the cervical os; however, foams are effective for short periods of time only, and reapplications are necessary. This increases their cost. They also contain nonoxynol-9 and may cause irritation. Failure rates up to 25% are reported. When used in conjunction with the condom, excellent pregnancy protection has been demonstrated, reaching 96% effectiveness.

INTRAUTERINE DEVICES (8,9)

Intrauterine devices (IUDs) are the most widely used contraceptive worldwide. IUDs contain copper or release a progestin. The copper devices induce an inflammatory response that prevents viable sperm from reaching the fallopian tubes. Progestinreleasing IUDs inhibit sperm survival and fertilization of ova; they are also thought to inhibit ovulation and implantation of a fertilized embryo. Both levonorgestrel IUDs reduce menstrual bleeding, causing oligomenorrhea in 70% and amenorrhea in 30% of cases. This is an advantage for women bothered by heavy bleeding and a disadvantage for those who prefer to have regular menstrual cycles. Even though not unexpected, the onset of amenorrhea warrants a pregnancy test.

Effectiveness

The 0.1% to 0.8% first-year pregnancy rates with these IUDs are the lowest attainable with any form of reversible birth control and are comparable with those of surgical sterilization. Adherence rates are higher than with oral contraceptives. Another advantage is the lack of systemic effects, a major problem with oral contraceptives (see later discussion). One limitation is expulsion, which occurs in 3% to 10% of women with copper IUDs and 1% to 6% of women with progestin IUDs. Expulsion is particularly frequent in nulliparous women. The copper IUD remains effective for 8 to 10 years. There are two levonorgestrel-releasing IUDs available: Mirena (higher dose, remains effective for 5 years) and Skyla (lower dose, smaller, remains effective for 3 years).

Risks

Modern IUDs do not confer an increased risk of pelvic inflammatory disease (PID) among women at low risk for sexually transmitted disease (STD). However, copper IUDs may increase
the likelihood of PID and subsequent tubal infertility among women exposed to an STD. The levonorgestrel-releasing IUD may reduce the risk of PID and is therefore a better choice for women who are not monogamous or regularly using barrier methods of contraception.

IUDs are associated with lower risk of ectopic pregnancy compared with no birth control but higher risk compared with hormonal methods that prevent ovulation. This is especially true for the levonorgestrel-releasing IUD; as many as 50% of pregnancies that occur with it in place are ectopic. On the rare occasions when pregnancy does occur despite IUD use, which is typically in the first year of use, its location should be ascertained immediately.

ORAL CONTRACEPTIVES (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 and 41)

The combination pill inhibits ovulation by preventing cyclic release of follicle-stimulating hormone and luteinizing hormone; alters the cervical mucus, thereby decreasing sperm motility; and alters the endometrial lining to inhibit implantation. Combination pills consist of ethinyl estradiol and a progestin (norethindrone, norgestrel, levonorgestrel, ethynodiol diacetate, desogestrel, and norgestimate). Most pill cycles are 28 days long. Pill packets contain 21 or 28 pills, depending on the brand. Twenty-eight-day packets contain placebo pills for part or all of the last week of the pill pack. Combination pills can be monophasic (same dose each day in active pills) or triphasic (dose of progestin increases weekly). Patients are instructed to start on the first Sunday of their menstrual cycle (“Sunday Start”; recommend use of backup method for first month) or the first day of bleeding (“First Day Start”; no backup necessary). Extended-cycle regimens, containing 84 active pills and 7 inactive pills, became available in 2003 for women who want to reduce the frequency of menses, although any pill pack can be “cycled” by eliminating the placebo pills and starting with a new pack for 3 months.

Effectiveness

Combined oral contraceptives have use effectiveness rates that are significantly better than barrier methods and spermicides. Reported failure rates are as high as 5% to 10% with typical use, but when used correctly, only 1 failure per 100 users per year.

Preparations

Dozens of combination preparations are available in the United States. In general, it is most useful to renew any prescription with which a patient is satisfied, as long as it is safe and the patient has no new symptoms or habits that warrant discontinuation of any oral contraceptive. Because of the concern that cardiovascular risks and venous thrombotic events might increase with estrogen dose and progestin potency, emphasis in recent years has been on the use of preparations that have the lowest effective estrogen dose (20 to 35 µg of ethinyl estradiol) and the least progestin potency (levonorgestrel or norethindrone).

A Starting Low-Dose Program

A recommended general approach is to begin with a monophasic pill containing 30 to 35 µg of ethinyl estradiol. All progestins have relatively low estrogenic effect, except for ethynodiol. Using the lowest possible progestin dose helps to minimize bothersome side effects such as increased appetite, steady weight gain, breast enlargement, acne, mood swings, and depression. All low-dose preparations need to be taken consistently to be maximally effective and to minimize the chances of breakthrough bleeding. Generic birth control pills offer a range of options at a much lower cost to the patient or insurer, without any known difference in efficacy. It is prudent to reserve the high-cost oral contraceptive pills for patients who have a medical need for a specialized contraceptive pill.

A good basic pill to start with contains 1 mg of norethindrone and 35 µg of ethinyl estradiol (generic version of Necon 1/35). Patients who have a history of symptoms suggesting hyperresponsiveness to endogenous estrogens (premenstrual breast engorgement and soreness, cyclic weight gain, heavy periods) may benefit from a preparation containing a low estrogen dose and a progestin with minimal estrogenic effect. Examples are Necon 0.5/35 (norethindrone 0.5 mg/ethinyl estradiol 35 µg) or Ovcon (ethinyl estradiol 35 µg and norethindrone 0.4 mg). A patient bothered by acne or hirsutism should be given a preparation with low androgenic progestin such as ethynodiol, desogestrel, or norgestimate (Table 119-2). Monophasic preparations are superior to triphasic pills in suppressing ovarian function and should be the pill of choice in women with a history of large ovarian cysts.

Lower-Dose Preparations

Lower-dose agents have higher rates of spotting, breakthrough bleeding, and amenorrhea. Moreover, women who use oral contraceptives containing less than 30 µg of estrogen may experience a greater chance of pregnancy. To counteract this reduced efficacy, newer pills with 20 µg of ethinyl estradiol have longer hormone cycles with as few as 2 days of placebo in a 28-day pack. In an attempt to improve rates of breakthrough bleeding and pregnancy associated with low-estrogen/weak-progestin formulations, manufacturers developed triphasic formulations (e.g., Ortho-Novum 7/7/7, Tri-Norinyl, Triphasil). The rationale is to more closely mimic normal ovarian patterns. Efficacy is similar to that obtained with other low-estrogen/weak-progestin preparations.

Progestin-Only Pills

Progestin-only pills—the minipill—are available and prescribed for women who should not take estrogens. Lactating women, women with complex migraine headaches or migraines with aura, women older than 35 years who smoke, and women with hypercoagulable states or thromboembolic disease may be given this preparation. Other women who might fare better with the progestin-only pill include those who are breast-feeding or
immediately postpartum (<6 weeks) and women with cardiovascular disease, hypertension, or diabetes.

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