Enhancing contraception:
A comprehensive review

This review covers familiar and emerging contraceptive methods, comparing the risks and benefits of each. These basics will help you connect patients with the most acceptable form of contraception for them.

Kristine A. Himmerick, MPAS, PA-C

The author is a recent graduate of the University of Iowa PA program and currently practices pediatrics in Montrose, Colo. She has indicated no relationships to disclose relating to the content of this article.

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Nearly half of all pregnancies in the United States are unintended¹—a fact that is both astounding and unacceptable in an era of rapid advances in medical technology and pharmacology. The problem is not the result of too few contraceptive options, but rather of ineffective communication about acceptable options. Contraceptive counseling requires a delicate balancing of the needs of each patient with the efficacy, mechanism of action, risks, and benefits of each available method. One study suggests that adherence to contraceptive regimens improves when women are provided with comprehensive information in a respectful, patient-centered approach.² Because both patient education and respect are foundations of the PA mission, we hold a pivotal role in enhancing contraception.

Influencing factors

In the contraceptive counseling session, try to elicit the reasons that might influence a patient to adhere to a particular method of contraception. Some of these factors include medical history, experience with contraception, partner support, convenience of use, protection against sexually transmitted diseases (STDs), effects on lifestyle, frequency of intercourse, desire for children in the future, and personal, religious, or cultural convictions. The ongoing cost of contraception is another factor to be discussed with the patient. Any provider who offers contraceptive counseling should be familiar with the cost of contraceptive options and assistance programs available in the area.

Because no form of contraception is guaranteed to prevent pregnancy, it is also important to assess how much risk a patient is willing accept that a pregnancy may occur. Contraceptive efficacy is measured as the number of women out of 100 who become pregnant unintentionally in the first year a method is used (see Figure 1). This definition is further divided into perfect use (women who report using the method consistently and correctly every time) and typical use (women who report occasional incorrect or inconsistent use). Examples of typical use include occasionally missing a daily pill or occasionally not using a diaphragm. The efficacy numbers generally quoted to patients are the typical use values. 

Behavioral methods of contraception

Natural family planning/Fertility awareness methods (NFP/FAM) Some women may be unwilling to employ artificial contraceptive methods for personal, religious, or cultural reasons, preferring NFP or FAM. These approaches can be effective for a woman with regular menses and a partner committed to helping her make the method work. A woman can approximate her time of ovulation by maintaining a calendar of menses, noting changes in cervical mucus, and recording daily basal body temperatures. Near ovulation when fertilization will most likely occur, women may choose to abstain from intercourse (NFP) or use alternate methods such as withdrawal or condoms (FAM) to avoid pregnancy. Because of the variability in each woman’s cycle and the discipline required for successful implementation, this method has an inherently high failure rate. Behavioral methods require detailed patient training in order to be effective; educational materials for patients and clinicians are available from the Institute for Reproductive Health at www.irh.org.   

Withdrawal (coitus interruptus) This is another option for couples who choose not to use contraceptive devices or pharmacology. In this method the penis is withdrawn completely from the vagina before ejaculation occurs, in order to reduce the number of sperm introduced into the vagina. This method is highly dependent upon the man’s cooperation and ability to predict ejaculation. Withdrawal does not require a barrier and thus does not protect from sexually transmitted infections.

Lactation infertility When a baby nurses, a maternal surge in prolactin inhibits ovulation. In most cases, a woman must provide at least 90% of the baby’s feedings for this method to be effective. Lactation-induced amenorrhea may cease in as little as 3 weeks, so women who do not desire to become pregnant should use a second method of contraception soon after delivery. Safe options for contraception while breastfeeding are listed in Table 1.

Barriers and spermicides

Male condoms Besides preventing the passage of sperm into the female reproductive tract, latex or other synthetic male condoms also prevent the transmission of infectious particles, including HIV. Condoms made from natural membranes (such as lamb cecum) block sperm but may be permeable to smaller infectious particles and do not prevent STDs.

Female barriers Advances in contraceptive technology have provided women with three options for barrier protection: female condoms, diaphragms, and cervical caps. Women can insert these barriers into the vagina up to 8 hours before intercourse, which allows for more spontaneity than do male condoms. Female condoms, which are made of polyurethane and fit loosely inside the vagina with a firm external ring, do not provide adequate protection from STDs; nor do diaphragms and cervical caps, which fit tightly over the cervix and prevent sperm migration into the cervical canal. Diaphragms and caps must be fitted by a health care professional.

Spermicide To further prevent sperm from entering the cervical os, any method may be combined with the use of spermicide, which decreases sperm motility and nutrition by inhibiting fructolytic activity. The OTC spermicide most commonly available in this country is nonoxynol-9, formulated as vaginal cream, film, foam, gel, suppositories, and tablets. Spermicidally-coated condoms are also available, but they do not deliver enough spermicide to provide protection beyond condom use alone. Note that spermicides do not protect against STDs and may actually increase the risk of HIV transmission.³ In 2001, the World Health Organization (WHO) declared that nonoxynol-9 spermicide should not be used by women at risk of HIV infection.⁴ All sexually active persons with risk factors for acquiring STDs must be strongly encouraged to use synthetic barriers with every sexual contact, regardless of need for contraception.    

Pharmacologic contraception

Pharmacologic contraception exploits the physiologic actions of estrogen and progestin to block ovulation, alter cervical mucus, and stimulate atrophic change in the endometrium. The mechanism of progestin alone provides contraceptive benefit, although estrogen alone should not be used because it causes endometrial hyperplasia and increases the risk of endometrial cancer.

Combined oral contraceptive (COC) pills These regimens are currently the mainstay of contraceptive therapy, with most women experiencing only mild side effects. Despite their popularity, clinicians should be aware of the potential complications associated with COC use (see Table 2). Clinicians discovered many of the complications two decades ago when hormone concentrations were greater than 50 mcg per pill; WHO now recommends using the lowest effective dosage of hormones.⁵ Combined pills with less than 50 mcg of estrogen are safe and effective in women who have none of the contraindications to exogenous estrogen listed in Table 3.

Click table to see it full-size

Hormonal contraceptives increase the risk of stroke, acute MI, and venous thromboembolic disease. However, the risk attributable to COC use is low because the overall incidence of cardiovascular disease in women of reproductive age is low.^6,7 For women with relative contraindications or those who have significant side effects, the clinician and patient must determine together if the risks outweigh the benefits of remaining on a COC regimen. Alternatives may include a different form of contraception or a progestin-only oral contraceptive.

Commercially packaged COC pills provide 21 days of hormone followed by 7 days of placebo pills to allow for withdrawal bleeding. Recently, extended-cycle COCs have been introduced that allow for 1 week of withdrawal bleeding every 3 months with efficacy and safety equal to standard 28-day COCs.⁸ Any monophasic pill (equal quantity of hormone in each tablet) can theoretically be used in the same way by skipping the seven placebo tablets and starting a new package after taking the 21 active pills. Multiphasic pills are also available; these contain varying amounts of estrogen and progestin in the active pills and attempt to mimic natural hormone fluctuations and to provide the lowest effective dosage of hormone. Because of the varying amount of hormone in multiphasic pills, they must be used in only in the prescribed 4-week cycles.

Combined contraceptive patch Various delivery methods for hormonal contraception have been developed in an attempt to improve the poor adherence rates seen with daily pill ingestion. In one, a 4.5-cm square patch containing hormones is applied to the skin, allowing estrogen and progestin diffusion at a constant rate. Patients apply a new patch to the abdomen, buttocks, upper arm, or torso (but not breasts) every week and remove it for the fourth week to allow withdrawal bleeding. The patch may be less effective in women weighing more than 90 kg (198 lbs).⁹ When compared to COCs, the patch causes slightly increased nausea, breast pain, and irritation at the application site.¹⁰ Patch contraception has efficacy similar to COCs, and its unique delivery system improves compliance.^10,11

Combined contraceptive vaginal ring This system involves a 2-inch flexible ring that delivers low-dose estrogen and progestin directly into the vagina. The patient inserts one ring into the vagina and leaves it there for 3 weeks; then she removes it for 1 week to permit menstrual bleeding. Vaginal rings remain effective with minor deviations from the recommended protocol, and they have contraceptive benefit similar to COCs with the added advantages of improved hormone delivery and convenience.^12,13 Ninety-five percent of women reported that the ring was easy to insert and remove. In addition, 80% of women and 70% of partners did not sense the ring during intercourse.¹⁴ Ring and patch delivery systems maintain a constant serum hormone level, which decreases the side effects associated with pulsatile delivery from pill ingestion.

Progestin-only pills (POPs) Progestin alone provides contraceptive benefit when patients have contraindications to exogenous estrogen. Two factors make POPs less effective than COCs:

Progestin-only injectable An injection of progestin every 3 months circumvents the adherence problems seen with contraceptive pills.¹⁵ The injection works similarly to a POP by suppressing ovulation, inducing endometrial atrophy, and thickening cervical mucus. The progestin-only injectable has been studied extensively in an effort to understand its high discontinuation rates, side effects, and reversibility. Women often discontinue these methods due to amenorrhea, irregular bleeding, or heavy bleeding. Two studies reveal that fewer than 30% of women continue the injections after 1 year.^16,17 Continuation rates improve if women understand that menstruation may initially be irregular and that amenorrhea may result after a few injections.¹⁸ Those who seek reversible contraception may be poor candidates for these injections, as fertility may not return for 9 to 21 months after the last injection.¹⁵ Women must be educated on the potential side effects and benefits in order for these injections to be effective contraceptive options.

Intrauterine devices (IUDs) Two methods of intrauterine contraception are currently available in this country: a copper-coated IUD and a levonorgestrel-releasing IUD. Both are modifications to a T-shaped polyethylene frame that can be inserted into the uterus.

Although the precise mechanism of action remains elusive, IUDs likely function through multiple methods of action both before and after fertilization.¹⁹ IUDs mechanically create a sterile inflammatory reaction in the endometrium that makes it toxic to sperm and ova and prevents implantation.²⁰ The addition of copper coating enhances the inflammatory reaction,²¹ while levonorgestrel provides additional benefits similar to those of other progestin-releasing methods.¹⁹ Copper IUDs are approved for 10 years of continuous use, while progestin-releasing IUDs are approved for up to 5 years of use.^22,23

IUDs are generally well tolerated, but clinicians should be aware of the potential complications with their use, including ectopic pregnancy and infection. Although IUD users have a low risk of ectopic pregnancy, they appear to have significantly higher rates of ectopic pregnancy because they have many fewer pregnancies overall than do women not using IUDs. Infection may arise from the device itself, the insertion process, or high-risk sexual behaviors. Modern devices have monofilament tail strings that are consistently sterile when cultured and do not transmit infection. During the insertion process, however, infection can be transmitted, possibly leading to pelvic abscess.²⁴ Contamination of the endometrial cavity at the time of insertion results in infection in 0.1% of device placements.²⁵ Proper sterile technique can control this risk. Finally, women at high risk of acquiring STDs are at risk for pelvic inflammatory disease (PID) from the use of an IUD²⁶ and should use another method of contraception. 

Emergency contraception

Emergency contraception (EC) includes any method that acts to prevent pregnancy after intercourse and before implantation.²⁷ Postcoital pregnancy prevention can be achieved with POPs or COCs, and specific preparations are available for this purpose. Most commonly used is levonorgestrel (Plan B), 0.75 mg taken as a single dose within 72 hours of unprotected intercourse, with a second 0.75-mg dose taken 12 hours later. As listed in Table 4, daily COC pills can also be taken together as EC. The first dose of oral EC should be taken within 72 hours of unprotected intercourse, since efficacy improves with earlier administration. The majority of women experience nausea and vomiting, so antiemetics should be given as well.

Copper IUDs are an alternative to hormonal methods of EC and may be inserted to inhibit implantation up to 5 days after the earliest estimated date of ovulation.²⁸ IUDs used for EC have the added benefit of providing future protection from pregnancy. Mifepristone (Mifeprex, RU-486), given in a single low dose of 10 to 25 mg within 5 days of unprotected intercourse, has also been shown to be effective in the prevention of pregnancy,²⁹ although it remains highly controversial as a form of EC due to its abortive effects at doses greater than 200 mg.

Clinicians should discuss the option of EC with all sexually active female patients. The only absolute contraindication to oral EC is current pregnancy (although EC is not teratogenic). POPs are recommended over COCs in women with history of thromboembolic disease or current severe migraine. The clinician should offer EC to all sexually active women as pills to take home or a prescription with refills.²⁵ Advance provision of EC increases timely and appropriate use and does not adversely affect routine contraceptive use or sexual risk-taking behavior.³⁰ After using EC, a woman should return to the clinic for a follow-up pregnancy test if she does not menstruate within the next 3 weeks. When women present to the clinic for EC, clinicians should take advantage of this excellent opportunity to provide further contraceptive education.

Sterilization

Surgical methods of preventing fertilization are available to women and men by interrupting the fallopian tubes or the vas deferens. Tubal obstruction can be achieved with partial tubal removal or ligation, mechanical obstruction (clips, rings, coils, or plugs) or coagulation-induced blockage (electrical or chemical). Female sterilizations can be performed postpartum or on an outpatient basis through laparoscopy or hysteroscopy. The highest cumulative 10-year probability of pregnancy occurs after clip sterilization, and the lowest probability occurs after coagulation and postpartum partial salpingectomy.³¹ Male sterilization is safer, easier, and less expensive than female sterilization.³² The vas deferens can be ligated in the clinic under local anesthetic. For 3 to 6 months after male sterilization, sperm counts should be obtained to confirm azoospermia or immotility, since complete sterilization does not always occur. Although vasectomy reversal can be performed successfully in 50% to 70% of cases, men and women should be informed that surgical methods of sterilization are not intended to be reversible.³³ 

Looking ahead

Contraceptive methods have advanced dramatically in the past several years, and new techniques will continue to emerge. Future methods may include improved female barriers, more effective spermicides, single-rod progestin implants, combined hormone injections and implants, male hormonal methods, improved IUDs, immunocontraceptives for women and men, low-dose mifepristone for EC, and reversible sterilization.^34-36 We can expect these new methods to offer improved ease of use, enhanced efficacy, and decreased side effects.

To provide acceptable and effective contraception to patients, PAs must understand the available methods. A thorough history and physical examination are needed to elicit the patient’s reproductive goals and to determine any contraindications. Then, risks and benefits must be discussed and combined with the efficacy of and likelihood of compliance with each possible method. Prescribing contraception is a complex task, but it is essential to decreasing rates of unintended pregnancy and ensuring that patients can successfully control their fertility.   

REFERENCES

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