Definition

Birth control plays a major role in the reproductive and overall health of both men and women. The fertility status of a couple (or an individual) can be categorized in one of four ways:

• Wish to become pregnant at present time
• Ambivalent about procreation at present time
• Desire to avoid pregnancy at present time
• Desire no further children (desire to terminate childbearing) or desire no children at all

The desired number of children per family in the United States is now about two. Despite the availability of a number of contraceptive options, close to 50% of pregnancies in the United States are unplanned, and approximately 25% of babies born are unwanted at the time of birth.

Of particular concern is a subpopulation that is sexually mature yet not psychologically mature—adolescents. Fewer than one-fourth of the 4.5 million sexually active teenage girls use effective contraceptives consistently. Thus we are currently witnessing an epidemic of teenage pregnancies with more than 1 million teenage girls age 15 to 19 years becoming pregnant each year. One in ten U.S. teenagers age 15–19 becomes pregnant each year; this is the highest rate for any industrialized nation in the world. In the Netherlands, where the same percentage of teenage girls is sexually active, only 1 in 70 becomes pregnant. The failure in the United States to provide adequate sex education, adequate contraceptive options, and ready accessibility to contraceptives to teenagers leads to this unacceptably high rate of unintended pregnancies.

Technique

The clinician should explore with the patient her (or his) reproductive life plan, what method of birth control is currently being used, and what medical or surgical complications might be affecting the patient's current use of a contraceptive. The patient's ability to use a particular method reliably is a crucial consideration in the selection of methods. Both the patient and the clinician may find the effectiveness rates of the various methods an important determining factor (see Table 174.1).

Table 174.1

First-year Failure Rates of Birth Control Methods.

Assuming that the patient is a woman, the following questions will help define current fertility goals, need for birth control, use of birth control, attitudes toward birth control, and effects of birth control on menstruation, sexual activity, and general health. These questions may be provided to the patient in writing or may be asked by a physician or counselor.

• When, if ever, would you like to have a baby?
• What methods of birth control have you used?
• Have you ever been told not to use any specific method of birth control?
• Have you ever suffered any problems or experienced any complications from a birth control method?
• Describe your periods: regular or irregular, painful or not, heavy or light.
• About how often do you have intercourse?
• Are you currently using any method of birth control?
• Are you pleased with your current means of birth control?
• Is your partner pleased with your current means of birth control?
• Is your partner willing to cooperate in using a birth control method?
• Do you mind using a method that may interrupt lovemaking?
• Have you ever become pregnant when you did not plan to?
• If so, what did you do about your unplanned pregnancy?
• If you had an unplanned pregnancy in the near future, what would you consider doing?
• What are your current thoughts about sterilization?
• What are your current thoughts about abortion?
• How much can you spend on a birth control method?
• Do you receive medical or health care on a regular basis?

Basic Science

Birth control methods are designed to prevent conception or prevent or nullify implantation. Conception can be prevented by hormonally disrupting the menstrual cycle (pills), by physically blocking the passageway (barrier methods or sterilization), or, somewhat less successfully, by abstinence during fertile periods or withdrawal. Implantation is impaired via the use of a foreign body (intrauterine device) or via surgical removal (abortion).

The average American woman starts to menstruate at about 12.5 years of age and ceases menses between the ages of 45 and 55. In her lifetime, she may ovulate 400 times, conceive 3 to 4 times, and have 2 to 3 deliveries.

A basic understanding of the menstrual cycle is fundamental to understanding how many contraceptive methods work (see Figure 174.1). A woman's fertility is tied to monthly release of an ovum, although not all cycles are ovulatory. Ovulatory cycles tend to be more regular than anovulatory cycles, are more painful than anovulatory cycles, and are associated with midcycle pain (mittelschmerz) in some women.

Figure 174.1

A 28-day menstrual cycle. Not all cycles are 28 days long. It is the phase before ovulation that varies in length. (Courtesy of Contraceptive Technology.)

The average menstrual cycle is 28 days long. The first day of blood flow is considered day 1 of the cycle and marks the menstrual phase. During this menstrual phase, the endometrial lining sheds and the blood levels of estrogen and progesterone decline. Declining estrogen levels decrease the inhibition of the hypothalamus, which produces follicle-stimulating hormone releasing factor (FSH-RF) to stimulate the release of FSH and luteinizing hormone (LH) from the pituitary.

On day 5, the ovary enters the follicular phase and the uterus enters the proliferative phase. FSH stimulates the growth of several follicles in the ovary. Eventually, most of the developing follicles will atrophy while a dominant follicle matures. The LH causes the follicles to secrete estrogen, which acts to increase LH levels further but decrease FSH levels. As the estrogen levels continue to rise, the endometrium of the uterus thickens and the uterine glands enlarge. A positive feedback loop of rising LH that produces more estrogen, which in turn stimulates greater LH levels, culminates in an LH surge, a reference point in endocrinologic studies of the menstrual cycle. The surge promotes the maturation of the follicle, ovulation of the follicle, and formation of the corpus luteum from the ruptured follicle.

With the formation of the estrogen- and progesterone-releasing corpus luteum, the ovary enters a luteal phase and the uterus enters a secretory phase. Progesterone from the ovaries stimulates endometrial glands to produce a mucus-like secretion in preparation for implantation of a fertilized egg. This phase lasts 13 to 15 days in 90% of women; thus, a menstrual cycle that is shorter or longer than 28 days generally (except for cases of luteal phase deficiency) has longer or shorter menstrual and proliferative stages.

If fertilization occurs, the egg implants on the endometrium and the trophoblast produces human chorionic gonadotropin to maintain the progesterone secretion of the corpus luteum until the placenta is mature enough, in 6 to 8 weeks, to secrete its own hormones.

If fertilization does not occur, the progesterone secreted by the corpus luteum inhibits the hypothalamic production of FSH-RF, resulting in a fall of LH secretion by the pituitary. Without trophoblast stimulation, the corpus luteum atrophies 9 to 11 days after ovulation, thus causing the estrogen and progesterone levels to fall. The thickened lining of the uterus can no longer be maintained and is sloughed off.

Oral contraceptives provide two hormones. The estrogens in birth control pills inhibit ovulation via the effect on the hypothalamus and the subsequent suppression of pituitary FSH and LH; inhibit implantation of the fertilized egg; accelerate ovum transport; and cause luteolysis, or degeneration of the corpus luteum, thereby causing the fall of serum progesterone levels, which prevents normal implantation and placental attachment. The progestins in birth control pills create a thick cervical mucus that hampers the transport of sperm; inhibit capacitation required for sperm to penetrate the cells and macromolecular investments surrounding the ovum; inhibit implantation; and inhibit ovulation by a subtle disturbance in the hypothalamic–pituitary–ovarian functions and by modification of the midcycle surge of FSH and LH.

Intrauterine devices are thought to: (1) create a local foreign body inflammatory response that causes lysis of the blastocyst and sperm and prevention of implantation; (2) increase local production of prostaglandins to inhibit implantation; (3) increase motility of ovum in the fallopian tube; and (4) immobilize sperm as they pass through the uterine cavity. It is now felt that the IUD prevents contraception in most women through its effects on sperm as they pass through the uterine cavity. The copper in copper-bearing IUDs may compete with zinc to inhibit carbonic anhydrase and alkaline phosphatase activity, as well as possibly interfere with estrogen uptake and effects. Progesterone-elaborating IUDs may disrupt the proliferative–secretory maturation process to impair implantation.

Barrier methods of contraception include condoms, diaphragms, sponges, and cervical caps that prevent the sperm from entering the uterine cavity. The spermicides used with the diaphragm and cervical cap and incorporated into the sponge kill the sperm, thus providing additional contraceptive effect should any sperm bypass the barrier.

Fertility awareness methods allow women to practice abstinence during days of potential fertility. Methods used to detect fertile days include basal body temperature charting, observation of cervical mucus changes, or prediction through use of the calendar. Fertility awareness methods are also used to help couples plan when to have sexual intercourse if they are trying to conceive.

Sterilization is an irreversible method of preventing conception. In the vasectomized male, sperm transport is obstructed via ligation of the vas deferens. In the sterilized female, ovum transport is obstructed via ligation of the fallopian tubes.

Abortion is unsafe after the end of the second trimester. Products of conception may be removed through the use of several methods, both surgical and medical. The surgical methods include vacuum curettage (through 13 weeks" gestation), dilation and curettage, dilation and evacuation (the most common method used during 13 through 20+ weeks of gestation), and, very rarely, hysterotomy or hysterectomy. The medical methods include prostaglandins. hypertonic saline, and hypertonic urea.

Clinical Significance

The practicing clinician must be aware of the fertility goals and practices of patients for two basic reasons: the risks of pregnancy and the risks of contraception.

Pregnancy may adversely affect the physical or psychologic health of an individual, of a relationship, or of a family unit. Women at risk of having a less than ideal outcome of pregnancy for themselves or for their child include the following: those with high parity, recent delivery (less than 12 months), recurrent premature deliveries or stillbirths, a history of postpartum depression, age less than 15 or over 40 years, chronic hypertension, sickle cell disease, advanced heart disease, and, perhaps the most important in this context, women who do not wish to be pregnant.

Efforts to avoid pregnancy (contraceptives) are used by a great number of individuals. Most clinicians need to understand the potential complications of contraceptives. Table 174.2 summarizes the relative indications, contraindications, and complications of 12 different approaches to fertility control. In managing complications associated with contraceptive methods, for the most part it is best to avoid a polypharmacy approach that may include measures such as prescribing diuretics for pill-induced hypertension, pyridoxine for pill-associated depression, cafergot for pill-induced migraines, or leaving an IUD in place while giving antibiotic treatment for pelvic inflammatory disease. The remainder of this discussion focuses on some of the more serious complications and side effects of contraceptive use.

Table 174.2

Twelve Methods of Fertility Control.

Oral Contraceptives

The most serious side effects of pills are cardiovascular. Certain women are at greater risk of having heart attacks or strokes while on the pill. High-risk women include those who smoke; are over 35 years of age; have other health problems, such as hypertension, diabetes, heart or vascular disease; or have a family history of these problems. The excess annual death rate attributable to pill use is as follows:

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Age	Smoker	Rate
35–40	No	1/6,700
	Yes	1/2,000
Under 35	No	1/77,000
	Yes	1/10,000

Patients should be carefully taught the five early danger signals shown in Figure 174.2. Patients experiencing any of these signs should be thoroughly evaluated. Less serious symptoms may be managed by observation, dosage modification, or discontinuation of the pill.

Figure 174.2

The early danger signals associated with oral contraceptive use.

Amenorrhea: Rule out pregnancy, then observe or modify dosage. Spotting: Reassure the patient that spotting is common during the first three months of pill use. Rule out pregnancy, pelvic inflammatory disease (PID), and other gynecologic problems. Spotting may be managed by reassuring the patient, increasing the progestin dose, or increasing the estrogen dose. Initially, try to manage spotting or breakthrough bleeding by increasing the progestin in the pill provided to a woman. Depression: Accurately diagnose source of depression. Consider lowering the pill dose or even discontinuing the pill to see if depression improves. If serious, refer a woman for psychiatric help immediately. Headache: Diagnose etiology accurately. If the headache is felt to be associated with the pill, lower the dosage, switch to a progestin-only pill, or discontinue the method. Hypertension: Monitor the patient's blood pressure. If the hypertension continues, discontinue the pill and consider prescribing the minipill or an alternative method. Many clinicians feel that a method of birth control other than combined oral contraceptives should be found for a woman who has a diastolic blood pressure that is consistently greater than 90 mm Hg.

Intrauterine Devices

In IUD users, the most serious complications are perforation of the uterus and PID. IUDs have been associated with an increased risk of infertility. The Dalkon Shield presents the greatest risk of PID and should be removed in any woman who still has one in place. Because of the increased risk of pelvic infection and infertility, women desiring future pregnancies should be encouraged to use alternative birth control methods.

IUD users should be carefully taught the five danger signals in Figure 174.3. These signs must be diagnosed accurately and attended to immediately. Management of other symptoms may require removal of the IUD. Bleeding: For bleeding due solely to the IUD, remove the device if there is an associated endometritis, the hematocrit falls by 5 points or is 30 to 32%, the IUD is partially expelled, or the patient desires removal. Cramping or pain: Rule out partial IUD expulsion, pelvic inflammatory disease, spontaneous abortion, or ectopic pregnancy. Remove the IUD. After treatment or if no problem exists, another IUD may be inserted; consider a different type or size device. Pregnancy: Remove the IUD. Removal is associated with a 25% risk of spontaneous abortion. If the IUD is left in place, observe the patient carefully for spontaneous abortion (50% risk), ectopic pregnancy (5% risk), and an increased risk of septic abortion.

Figure 174.3

The early danger signals associated with use of an intrauterine device.

As of 1989, the two IUDs available in the United States are the Progestasert System, which elaborates a small amount of the hormone progesterone, and the Copper T-380A (or ParaGard), which elaborates copper. The Progestasert System must be replaced at 1 year. It is quite likely that the Copper T-380A remains effective for longer than the 4-year limit currently recommended.

References

1. Contraceptive technology update. A monthly newsletter reporting latest developments in the field of contraception. American Health Consultants, Atlanta, GA.
2. Hatcher RA, Guest FJ, Stewart FH, et al. Contraceptive technology, 1988–1989. New York: Irvington, 1986.
3. Population reports. A series of articles containing references, available from the US Agency for International Development.