Teen pregnancy rates in the United States have been declining since the early 1990s—a decline primarily attributable to more effective contraceptive practice, not to a decline in sexual activity. At the same time, however, US teen pregnancy rates remain persistently higher than those in most developed countries. According to 2006 data from the Guttmacher Institute, a nonprofit sexual health policy and research organization, approximately 750,000 teenagers annually still become pregnant, with 34% of these pregnancies ending in abortion.1 Most of the pregnancies are unplanned.2,3
By age 17, approximately half of adolescents are sexually active. Most teens are unlikely to use contraception regularly, and many do not use it at all. Statistics show that a sexually active teen has a 90% chance of becoming pregnant within a year if she is not using any form of contraception. While public education efforts have improved the rate of contraceptive use, 22% of teenage girls do not use any form of protection the first time they have intercourse.3 Only 35% of high school students report consistent use of contraception during every act of sexual intercourse.4 These behaviors put them at risk for sexually transmitted infections (STIs) and unintended pregnancy.
Once teens become pregnant, only two thirds receive adequate prenatal care—a matter of great concern for several reasons. Young mothers have more low birth weight babies and more premature births. Children of young mothers have more childhood health problems and increased hospitalizations. These children are at higher risk for behavior and learning difficulties. Most research connects health and learning deficiencies to adolescent parents' low economic and education levels.4
Health professionals agree that the numbers of teenage pregnancies and termination rates are too high, but reducing the high rates of adolescent pregnancy continues to be a challenge for clinicians. Emergency contraception (EC) has the potential to prevent 75% to 85% of unintended pregnancies and to eliminate approximately 50,000 elective abortions per year.2 In an adolescent patient population where contraception compliance is a serious issue, EC should be supported as an essential component to pregnancy prevention.
EMERGENCY CONTRACEPTION
Postcoital contraception has been used in humans since the 1960s, when a physician in the Netherlands provided high-dose estrogens to a 13-year-old rape victim.4 Since the 1970s, high-dose estrogen therapy has been combined with a progestin regimen and known as the Yuzpe method. Additionally, a progestin-only option (levonorgestrel) was created in an attempt to reduce the side effects associated with high-dose estrogen, most notably nausea and vomiting.
What is EC? The same hormones found in oral contraceptives (OCs) are used for EC. When taken in a concentrated dose within 72 hours of unprotected intercourse, EC can prevent pregnancy. Studies have shown a potential benefit at more than 120 hours postintercourse, but FDA guidelines for approved use specify a maximum of 72 hours.1
The confirmed mechanisms of action for EC include delaying or hindering ovulation, disrupting follicular development, or interfering with the maturation of the corpus luteum.5 Additionally, several theories of action have not been clinically proven, such as inhibition of fertilization and alteration of cervical mucus.1 EC is ineffective if a fertilized egg has successfully implanted within the uterine wall.
Safety The hormones in EC have been used in OCs taken by millions of women for decades. Serious complication rates, which are related to the estrogen component, have been proven to be extremely low. There is no associated toxicity with hormone use, so there is little danger in inadvertent overdose. There are no addictive properties to the hormones. In fact, the side effects—such as menstrual irregularities and nausea—may actually discourage women from using EC repeatedly. There have been no deaths or other serious consequences of an acute overdose of EC hormones. Decades of research show no risk or teratogenic ramifications of hormone exposure if a pregnancy has already been established.6
Patient screening The clinician should confirm that unprotected sexual intercourse occurred within the previous 72 hours before providing a prescription for EC. The focus should be on the exact number of hours since intercourse and on the date and normality of the last menstrual period. Clinicians should also ask about current or recent use of contraception and safe sex precautions to facilitate planning for future routine contraception. Neither a pelvic examination nor a pregnancy test is required before treatment, but these may be indicated if the patient may already be pregnant. Parental permission is not required for dispensing EC to an adolescent (see Table 1).
Treatment options The Yuzpe regimen consists of the combination of 100 mcg of ethinyl estradiol (EE) and 0.5 mg levonorgestrel divided into two equal doses and taken 12 hours apart. Most combined OCs can be used as EC if dosed at the same hormone levels as the Yuzpe method.
Nausea and vomiting, breast tenderness, fatigue, and headache are common with EC. However, use of an antiemetic 1 hour before dosing can reduce these effects. The majority of women taking EC will have a normal period on time, although irregular bleeding or spotting may occur, especially with repeated use. A meta-analysis of several clinical trials shows that EC has a 70% to 75% efficacy rate if used within the recommended time interval after unprotected intercourse.7 However, for pregnancy prevention, EC is not as effective as good compliance with most regular forms of contraception.
Plan B is a prepackaged EC product containing two 0.75- mg levonorgestrel pills to be taken 12 hours apart. Recent studies have shown that taking both pills at the same time works just as well and may increase compliance.8 According to von Hertzen and colleagues, the progestin-based products are more effective than the combination pills, with pregnancy prevention rates of 88% and 75%, respectively.9 Because of the improved side-effect profile, better efficacy, and ease in dosing, progestin-only Plan B may be a better choice for an adolescent population.
IMPACT OF EMERGENCY CONTRACEPTION
Gold and colleagues conducted a randomized prospective study comparing a cohort of adolescents who received EC education and a single dose of EC to be used if needed to a group receiving EC education alone.10 Researchers told those provided with education alone that EC would be available to them through the clinic if needed. The aim of the study was to ascertain whether providing EC in advance would lead to higher sexual and contraceptive risk-taking. Subjects were predominately African-American, with a mean age of 17.1 years; nearly half were Medicaid recipients. A 6-month follow-up showed that providing EC in advance facilitates its earlier use and decreases overall pregnancy rates. Advance EC provision had no negative influence on the teenagers' use of routine contraceptive methods. In addition, there were no more sexually transmitted infections or rates of unprotected intercourse among EC users as compared to controls.10
Raine and colleagues completed a controlled trial of female participants aged 16 to 24 years, 76% of whom were members of an ethnic minority, who attended a publicly-funded family planning clinic.11 About half had been pregnant before. As with the Gold study, patients were assigned to receive EC education and a single dose of EC in advance or education alone. Researchers found that advance provision of EC was the strongest predictor of EC use, after controlling for contraceptive method, pattern of contraceptive use, and frequency of unprotected sex. There was no significant increase in unprotected intercourse. Increased knowledge alone, without advance medication supply, did not increase requests for EC or promote behavior change.11
Stewart and colleagues performed a retrospective examination of the impact of using EC on reproductive health outcomes. Participants were aged 13 to 21 years, 63% African- American, in an urban, hospital-based adolescent clinic. This trial investigated whether prescribing EC affected pregnancy rates, STIs, number of sexual partners, age at first intercourse, and the scheduling of annual gynecologic examinations. Researchers found no associated poor reproductive health outcomes with the prescription of EC. Quite the opposite, their data showed that EC use may encourage the initiation of gynecologic care, thus providing an opportunity for STI testing and counseling.12 While limited original research exists on use of EC by adolescents, these studies demonstrate no behavioral or health consequences and validate EC use within pediatric practice.