Prevention of Unintended Pregnancy and Sexually Transmitted Diseases in Adolescents

Overview
In 1987 the Canadian Task Force on the Periodic Health Examination recommended that physicians who see adolescents should advise those who are sexually active about the correct use of appropriate contraception (B Recommendation). Review of more recent evidence has not altered this recommendation, however oral contraceptives have been identified as the method of choice for adolescents in combination with a condom to protect against sexually transmitted diseases (STDs). Evidence from school-based clinics and community-based programs aimed at the reduction of adolescent pregnancy and STDs has also been evaluated, and supports the preventability of unintended teen pregnancy.

Burden of Suffering
In 1989, there were 39,600 teenage pregnancies in Canada. The teenage pregnancy rate for Canada (pregnancies per 1,000 women aged 15-19) was 44.1, down from 53.4 in 1975.

Teenage pregnancy levels are much lower in Canada than in the United States. In 1985, there were 37 pregnancies per 1,000 Canadian females aged 15-19 compared with 95 pregnancies per 1,000 females of the same age in the United States. In 1985, the fertility rate for Canadian teenagers (23 births per 1,000) was less than half that of the U.S. teenagers (52 per 1,000). The proportion of teenagers accepting abortion is comparable (38% in Canada and 44% in the U.S.) so that in 1985, the abortion rate for Canadian teenagers was 14 per 1,000, about one third of the U.S. rate (42 per 1,000).

The Risks/Effects of Teenage Pregnancy
The most serious physical risk to the teenage parent is death from pregnancy complications. For girls under 15 years the complication rate is 60% higher than the rate for all women and 2.5 times higher than the rate for mothers 20 to 24 years old. However, the increased risk of maternal complications may be associated more with socioeconomic factors than with age.

Teen mothers can expect to complete less education than those who do not bear children early. Teen mothers also reach lower levels of work success and of long-term income, and feel less satisfied with their vocational achievements. Satisfaction with career progress is also lower for married teenagers with children compared to married teenagers without children.

Adolescent mothers who marry subsequent to their child’s birth are more likely than other adolescent couples to divorce or separate. Most teenage families with children are single-parent families.

Infants born to mothers less than 15 years of age are twice as likely as other infants to weigh less than 2,500 g (5 lb, 8 oz), a factor associated with increased infant mortality. 6.7% of live births in Canada during 1990 to women aged <20 years were of infants weighing <2,500 g, compared to 5.5% low birth weight babies born to mothers of all ages. Infants born to mothers less than 17 years of age are three times more likely to die in the first 28 days of life. However, cigarette smoking, poor gestational nutrition, low pre-pregnancy weight, primiparity and short stature are probably more important risk factors than maternal age.

Thus, adolescent pregnancy and childbearing may carry increased medical risk for mother and baby as well as lasting social, academic and economic disadvantages for mother, father and children. Except for academic and economic disadvantage, the evidence is weakened by lack of control for confounding variables.

Sexually Transmitted Diseases
38,074 cases of genital chlamydia, 9,451 cases of gonococcal infection and 1,196 cases of syphilis were reported in Canada in 1992.

Given the prevalence of STDs in the adolescent population, the spread of HIV is particularly worrisome to health care providers. As of January 1, 1992, 22 cases of AIDS were reported in Canadians aged 15-19 years (<1% of all cases; 8 were reported in the 10-14 year age-group) and 1,092 cases (20%) were reported for those aged 20-29 years. Chapter 58 on HIV provides more extensive discussion of risk groups; there are several other related Chapters on STD prevention/screening.

Maneuver

Counselling for Contraception
All physicians who see adolescents should assess whether those who are sexually active are practising appropriate contraception. Although some physicians may be uncomfortable discussing these matters with young people, the third-person approach may be useful (e.g., "Some people your age are dating, some are having sexual intercourse. How about you?".)

Durant and colleagues<1> developed a model that can be used clinically to anticipate and recognize the multiple inter-relationships between factors that usually influence adolescent contraceptive behaviour. However, findings from empiric tests of the model indicate that among low socioeconomic black female adolescents, only a small part of the variation in frequency of intercourse or of engaging in unprotected coitus was explained. Clinical attempts to identify adolescent patients at risk of pregnancy using only one or two criteria will probably be unsuccessful. Thus, all adolescents should receive counselling.

Teenage Use of Contraception and Compliance
Of all age groups, teens are the least likely to practice contraception. As one study noted "...the most notable feature of adolescent contraceptive behaviour is inconsistency." Although adolescents are thought not to visit a physician very often, a random sample of 1,000 teenagers in Ottawa (response rate 73%) revealed that 85% had seen their physician in the preceding year but only one-third of sexually active girls had ever discussed contraception with their physicians.

To eliminate the risk of pregnancy, an adolescent should understand that the only absolute method of contraception is abstinence. When this is not the adolescent’s choice, however, appropriate contraceptive options should be offered.

Studies have shown that adolescent compliance is determined in part by the relationship established with health care providers. Accessible clinic hours, positive attitudes in the reception area, time spent waiting for the physician, care taken with the examination and assurances of confidentiality are all factors associated with adolescents’ compliance. A further consideration may be financial as many adolescents have limited financial resources. Additionally, physicians should be open to some female adolescents’ preference for a female examiner. Table 1 identifies actions a physician can take towards ensuring compliance. The effectiveness of these steps in ensuring compliance has not been systematically evaluated.

Contraceptive Options
Table 2 summarizes the available adolescent contraceptive methods with their advantages and disadvantages.<2> Table 3 provides additional information on estimates of contraceptive failure by type of contraception method over its first year of use.<3>

Oral Contraception
The oral contraceptive pill is highly effective in preventing pregnancy using reversible means. It has been reported to be the overwhelming favourite prescription method of contraception for adolescents (84% vs. 4% for IUD and 11% for diaphragm).<4> Additional advantages include its relative low cost and ease of use.

At the same time, however, clinicians are concerned that by relying solely on an oral contraceptive (OC), adolescents are leaving themselves open to STDs and particularly to HIV/AIDS. Experts recommend that adolescents who are sexually active should be advised to use condoms in combination with oral contraceptives.<5> This combination has not been evaluated.

Case-control studies have shown that OC’s reduce the risk for endometrial cancer,<6> epithelial ovarian cancer,<2,7> pelvic inflammatory disease,<8> toxic shock syndrome<9> and ectopic pregnancy.<10> The potential association between OCs and cervical neoplasia is unsettled.<2> There is also some concern regarding a possible association between breast cancer and the use of OCs. However, many of the case-control studies evaluated in meta-analysis< 11,12> were of low quality, without protection from bias or from the potentially confounding effects of duration of lactation, induced abortion, recent pregnancy or a history of diseases that are associated both with reduced use of OCs and reduced risk of breast cancer. One study<13> suggested that prognosis for breast cancer is worse for those who start oral contraceptives at an earlier age. Further evaluation is required.

While most epidemiologic studies have shown an association between oral contraceptive use and an increased risk of venous thrombosis and embolism, the risk for teenagers is very small. Finally, OCs can improve the quality of life by conferring protection against a number of common ailments that affect teenagers: primary dysmenorrhea, benign breast disease, ovarian cysts and iron deficiency anemia.

Expert opinion supports the use of OCs by teenagers as a safe method to avoid unwanted pregnancy since the overall risks of taking OCs are much less than the risks of pregnancy. Low-dose OCs have not been linked with either heart attack or stroke in contemporary U.S. studies and the evidence regarding breast cancer is contradictory. While the overall risk of thromboembolism in oral contraceptive users may be increased over that of the general population, the risk to teenagers, especially those who do not smoke, is minimal. As with all medical choices, the benefits of a treatment must be weighed against potential risks.

Benefits/Risks of Intrauterine Device (IUD)
While compliance is assured with intrauterine devices and effectiveness is comparable to that of OCs, they provide no protection from sexually transmitted diseases and the risk of adverse affects associated with IUDs appears to be higher for adolescents. Expert opinion supports their use mainly for older women in stable monogamous relationships.<14>

Barrier Methods and Spermicides
In their recent review,<15> Rosenberg and Gollub reported that observational studies show that condoms offer widely divergent degrees of protection against sexually transmitted diseases. Meta-analysis shows that for most outcomes, condoms decrease infection rates by approximately 50%. While protection seems to increase with more consistent use, condoms may not protect against organisms transmitted by external genital contact. The rate of condom use among 15-19-year old males in the United States was 58% in 1988, more than double the rate reported in 1979 (21%); 20% of sexually experienced females reported currently using condoms (47% at first intercourse), compared with 11% in 1982. Condoms are widely available but are less effective in preventing pregnancy than IUDs or OCs.

Foams, diaphragms and creams are unpopular with adolescents in North America.<2,16> Each of these options interferes with spontaneity, requires the adolescent to plan ahead, requires motivation and familiarity with technique, and is "messy". Diaphragms and cervical caps, which are assumed to be used in conjunction with spermicide, leave a portion of the vagina unprotected; observational studies indicate a reduction in sexually transmitted diseases of 50-100%.<15>

Long-Acting Contraceptives
The impact of new long-acting contraceptives such as the progestin implant (Norplantā) on the reduction of adolescent pregnancy is currently unknown and will likely depend on the cost and availability of the method and on teens’ acceptance of these methods (including insertion discomfort and tolerance of menstrual irregularity). One observational study suggests Norplant is well accepted by adolescents.<17> Compliance is assured and effectiveness is high, but the methods again offer no protection from STDs.

Implant systems (for men) are under investigation as are vaginal rings releasing levonorgestrel and injectable hormone contraceptives. Birth control "vaccines" are also being developed, the most advanced being a vaccine inducing antibodies against human chorionic gonadotrophin (HCG).

The Morning-After Pill
Postcoital contraception (PCC) (the morning-after pill/ Ethinyl estradiol/dl-norgestrel in combination) has been shown to prevent pregnancy for most women when given after sexual intercourse. Termination of the pregnancy was not achieved for 1.1-2.0% of women treated, resulting in 15-30% of the expected number of pregnancies.<18-21> Side-effects include nausea (50%) and vomiting (20%). Women who rely on barriers, spermicide, withdrawal or periodic abstinence should be informed about the "morning-after pill".

Effectiveness of Prevention and Treatment

The Primary Care Physician
There have been no studies evaluating whether physicians identifying sexually active teenagers and counselling them on contraception will lead to more appropriate knowledge and behaviour. Most studies have evaluated interventions provided by non-physicians. However, the success of these interventions demonstrates that unintended pregnancy is preventable. There is no indication that physicians would be less successful.

A randomized controlled trial of 75 sexually active females in a clinic setting also showed that education programs increased knowledge of AIDS (p<0.001).<22> No significant differences were noted regarding attitudes or condom acquisition and other changes in behaviour were not addressed. School-based AIDS-prevention curricula have had modest effects.

Community-based Programs
A recent report documented a successful community-based program to reduce adolescent pregnancy in counties of South Carolina characterized as rural, low income and undereducated. Their public health approach involved teenagers, parents, community leaders, ministers, schools, churches, and community groups. School sex education, use of mass media and training of adult leaders in the community were all included. The estimated pregnancy rate declined 35%, compared with pre-intervention levels (95% confidence interval (CI): -14% to -57%). Comparison communities (no intervention) had 5-16% increases in the rate of teenage pregnancy (p<0.002). While the counties were comparable in terms of racial/ethnic composition, population density, income, and education, the comparison communities initially had lower estimated pregnancy rates (35-53% versus 61% in the target community).<23>

School-Based Programs
Most of the evidence regarding school-based programs (SBPs) comes from the United States. Most SBPs report a rate of use exceeding 75% of the school population once teens become aware of available services. An evaluation of the Baltimore SBPs’ attendance suggests that their accessibility rather than any new or newly packaged information about sex, family planning or other new services was responsible for high student use.<24> St. Paul, Minnesota<25> and western Massachusetts<26> studies have shown that birth rates for teenagers can be reduced by more than 50% without major reliance on abortion, in a population which is not upper middle class, not college bound, and which has traditionally been viewed as very hard to reach.

Table 4 summarizes a number of examples of effective community-based and school-based programs operating in the United States.<23-29> This is grade II-3 evidence that comprehensive school-based efforts to lower the rates of teenage pregnancy can be effective.

Sex Education in the Schools
Education programs and computer games are effective in providing at least short-term knowledge and attitudinal change in adolescents but school sex education by itself appears to have little or no effect on adolescent sexual activity or pregnancy rates. However, a study of 536 low-income minority students in Atlanta showed that those who participated in a family planning outreach program for eighth graders led by older students, were less likely (p<0.01) to report initiation of sexual activity by the end of the 9th grade (24% versus 39% of students had not had sexual intercourse).<28>

Recommendations of Others
In 1989, the U.S. Preventive Services Task Force<30> recommended that clinicians should obtain a detailed sexual history from all adolescent patients. Empathy, confidentiality and a nonjudgemental supportive attitude were stressed. It was recommended that clinicians involve young pubertal patients and, where appropriate, their parents in early, open discussion of sexual development and effective methods to prevent unintended pregnancy and sexually transmitted diseases, and that sexually abstinent adolescents be encouraged to remain abstinent. Oral contraceptives and barrier methods (with spermicide) were recommended as the most effective means of reducing risk in sexually active persons, and complete sexual abstinence as the most effective method overall. The U.S. Task Force stated that sexual abstinence and the maintenance of a mutually faithful monogamous sexual relationship should be emphasized as two important measures to reduce the risk of sexually transmitted diseases. Patients who engage in sexual activity with multiple partners or with persons who may be infected with sexually transmitted organisms should be advised to use condoms and instructed in their proper use.

The American Ad Hoc Committee on Reproductive Health (Sub-committee of the Society for Adolescent Medicine)<5> and the Committee on Adolescence of the Council on Child and Adolescent Health<31> advocate more physician training regarding pregnancy counselling for adolescents. The Council also recommends that pediatricians who do not want to counsel their teenage patients about sexual matters, refer their patients to counselling facilities experienced and sensitive to the needs of adolescents.

Conclusions and Recommendations
Given prevention program successes in community- and school-based clinics, there is fair evidence that physicians can reduce the toll of unwanted pregnancy by provision of education and contraceptive services, by involving pubertal patients and, where appropriate, their parents in early, open discussion of sexual development, prevention of sexually transmitted diseases, and prevention of unwanted pregnancy. Physicians caring for sexually active adolescents should address their contraceptive practices and where indicated, should provide a combination of services: education, counselling, contraception and follow-up (this may include repeat D (Rh) blood group antibody screening before induced abortion or other obstetric procedures, see Chapter 11). Oral contraceptives combined with condoms are the first choice for adolescents who do not wish to be sexually abstinent.

Unanswered Questions (Research Agenda)
The following have been identified as research priorities:

1. Evaluating Canadian school-based clinics.
2. Evaluating the effectiveness of physicians in identifying sexually active and unprotected teenagers, counselling, prescribing contraceptives, and altering their behaviour
3. Examining the effectiveness of a more widely available "morning-after pill" program because the majority of teenagers are unprotected during their first sexual encounter.
4. Further research into the reasons for noncompliance with oral contraception and the development of creative and effective solutions for non-compliance. Research into the effectiveness of counselling adolescents in the use of condoms in combination with oral contraceptives and with spermicide is also recommended.

This review was initiated in January 1993 and recommendations were finalized by the Task Force in October 1993.

Acknowledgements
Funding for this report was provided by Health Canada under the Government of Canada’s Brighter Futures Initiative. The Task Force also thanks Dr. Steven Woolf, MD, MPH, Science Advisor, U.S. Preventive Services Task Force, Washington, DC and Assistant Clinical Professor, Department of Family Practice, Medical College of Virginia, Richmond, VA, USA for reviewing the draft report.

Full Citation
Feldman W, Martell A and Dingle JL. Prevention of unintended pregnancy and sexually transmitted diseases in adolescents. In: Canadian Task Force on the Periodic Health Examination. Canadian Guide to Clinical Preventive Health Care. Ottawa: Health Canada, 1994; 540-57.