STI - Epi Update

April 1998

Oral Contraceptive and Condom Use

Reported cases and incidence rates of some sexually transmitted diseases (STDs) in Canada have been falling. Despite that, rates of STDs continue to be well above average among Canadians aged 15-24, especially for chlamydia and gonorrhea¹. Therefore, it is especially important that Canadian youths protect themselves against STDs. Although delay of onset of sexual intercourse or abstinence are effective ways for youth to avoid STDs, the appropriate use of condoms is an effective way to reduce STD transmission among those who choose to be sexually active. Unrecognized or untreated infections can lead to severe complications among women, such as pelvic inflamatory disease (PID), ectopic pregnancy and infertility. Intact latex condoms provide a continuous mechanical barrier against bacteria such as chlamydia and gonorrhea and viruses such as HIV, genital herpes virus and hepatitis B virus.

There is some concern that Canadian adolescents may be putting themselves at unnecessary risk of STD by choosing the oral contraceptive pill (OCP) for prevention of pregnancy while remaining at risk of acquiring an STD through unprotected sex. The problem appears to be with the interplay between the need to prevent pregnancy and the need to protect against STD. There is no single method that is completely effective in protecting against pregnancy and STD. The contraceptives that are most effective in preventing pregnancy, such as the oral contraceptive pill or an intrauterine device, offer no protection against STD. Condoms, on the other hand, offer protection against STD but are not the most effective contraceptive. This STD Epi Update outlines some of the relationships between use of oral contraceptives and condom use.

Use of the OCP must be accompanied by concomitant use of a condom

• Females who use the OCP to prevent pregnancy should also use a condom to protect against STD; however, research data indicate that females who use OCP do not necessarily consider using a condom for STD prevention².
• In a large Canadian study (n=1438) completed in 1995, only 27% of current OCP users reported concurrent use of condoms³.

STD risk is often underestimated by those who choose OCP

• A secondary analysis of the college/university subset of the Canada Youth and AIDS Study (mean age 19.7 years) found a complex relationship between the number of partners, condom use, and the use of OCP. Students with more sex partners were more likely to use OCP but less likely to use condoms⁴. In this study, for those who had 10 or more lifetime partners, regular condom use was reported in only 21% of males and 7.5% of females. Overall, regular condom use was reported in 24.8% of men and 15.6% of women.
• A 1994 study of American women at risk of HIV infection found that consistent OCP users were significantly more likely to assess their risk of HIV infection as "very unlikely" (73% vs. 58%), even after actual risk differences between groups had been controlled for⁵. Beliefs about the effectiveness of a method for pregnancy prevention may generalize to beliefs about its efficacy for disease prevention.
• In 1995, a Brazilian study of female partners of HIV-positive men found that oral contraceptive use was associated with a number of risky behaviors. These included anal sex, lack of condom use during anal sex, and high frequency of sexual contacts with a partner. Use of OCP was also associated with factors that may indicate a low perceived susceptibility to STD, such as no previous STD and asymptomatic clinical stage of HIV in a partner⁶.

Adolescents select pregnancy as the most worrisome outcome of sexual intercourse

• The Canada Youth and AIDS Study asked respondents which of AIDS, STD and pregnancy they worried about most as a possible outcome of sexual intercourse. Pregnancy was selected most often by all groups, grade 11 students, dropouts, and college/university students. Approximately 57% of Grade 11 students (male and female combined) and 59.5% of college/university students selected pregnancy as the most worrisome outcome of sexual intercourse. Conversely, only 4% of both the grade 11 students and the college/university students selected STD as the most worrisome outcome⁷.

• In 1992, a Norwegian study showed that the majority of adolescents who use contraception (pills or condoms) do so for protection against unintended pregnancy and not for protection against STDs². Use of OCP in this study was widespread among adolescents with high frequency of sexual intercourse and few sexual partners.

Serial monogamy does not protect against STD

• Adolescents often engage in serial monogamy (a series of monogamous relationships, one after the other), a practice that generally results in a lower, and sometimes unrealistic, perceived risk of STD and hence a lower perceived need for condoms against STD². Adolescents who practise serial monogamy perceive the relationship as 'feeling safe' and feel that their partner 'looks safe'.
• As partners become better known to each other, they are more likely to stop condom use and switch to OCP since they both feel a sense of trust and perceived safety from STD. Self-defined serial monogamy contributes to this sense of safety⁵.

Education on the role of condoms in STD prevention

• In 1996, an American study showed that receipt of an AIDS education intervention was associated with more effective contraceptive use and an understanding of the role of barrier methods in STD prevention. After an AIDS education intervention, more than 80% of a longitudinal study group of 383 African-American youths from ages 9 to 15 reported using condoms along with oral contraceptives⁸. This compared with a figure of approximately 66% at baseline. Intervention youth were also more likely to use barrier methods of birth control more effectively.

• In Canada, several programs have been developed to address sexual health education. Examples include Fisher and Fisher's Information-Motivation-Behavior Skills Program, the condom and pill campaigns (targeting health care providers) of Alberta Health, the Skills for Healthy Relationships educational program, developed at Queen's University, and the Guidelines for Sexual Health Education. Evaluations of these programs have led to the conclusion that they result in significant increases in condom use, decreases in the number of partners, and postponement of first sexual intercourse⁹.

References

1. Laboratory Centre for Disease Control. Sexually transmitted disease surveillance in Canada: 1995 annual report. CCDR 1998;24S1:1-32.
2. Traeen B, Lewin B, Sundet JM et al. Use of birth control pills and condoms among 17-19-year-old adolescents in Norway: contraceptive versus protective behavior? AIDS Care 1992;4(4):371-80.
3. Boroditsky R, Fisher WA, Sand M. Condoms: attitudes and practices of Canadian women. The 1995 Canadian Contraception Study. J Soc Obstet Gynecol Can (special supplement) December, 1996.
4. MacDonald NE, Wells GE, Fisher WA et al. High-risk STD/HIV behavior among college students. JAMA 1990;263(23):3155-9.
5. Galavotti C, Schnell DJ. Relationship between contraceptive method choice and beliefs about HIV and pregnancy prevention. Sex Transm Dis 1994;21(1):5-7.
6. Guimares MD, Muñoz A, Boschi-Pinto C et al. HIV infection among female partners of seropositive men in Brazil. Am J Epidemiol 1995;142(5):538-47.
7. King A, Beazley R, Warren W et al. Canada Youth and AIDS Study. Kingston: Queen's University, 1988.
8. Stanton BF, Li X, Galbraith J et al. Sexually transmitted diseases, human immunodeficiency virus, and pregnancy prevention: combined contraceptive practices among urban African-American adolescents. Arch Pediatr Adolesc Med 1996;150(1):17-24.
9. Maticka-Tyndale E. Reducing the incidence of sexually transmitted disease through behavioural and social change. Can J Human Sexuality 1997;6(2):89-104.