Research Brief

The Health Related Behaviors Survey (HRBS) is the U.S. Department of Defense's (DoD's) flagship survey for understanding the health, health-related behaviors, and well-being of service members. Fielded periodically for more than 30 years, the HRBS includes content areas that might affect military readiness or the ability to meet the demands of military life. The Defense Health Agency asked the RAND Corporation to revise and field the 2018 HRBS among members of both the active component and the reserve component. This brief discusses findings for the reserve component.

This brief reviews results for sexual behavior and health. Some of the results are also compared with Healthy People 2020 (HP2020) objectives established by the U.S. Department of Health and Human Services for the general U.S. population. Because the military differs notably from the general population (for example, service members are more likely to be young and male than is the general population), these comparisons are offered only as a benchmark of interest.

Sexual Risk Behaviors and Outcomes

Among all HRBS respondents, 15.9 percent (confidence interval [CI]: 14.9–16.8) reported having more than one sex partner in the past 12 months (Figure 1). In addition, 33.2 percent (CI: 32.0–34.3) reported having sex with a new partner in the past 12 months without using a condom (Figure 1).

Figure 1. Sexual Risk Behaviors and Outcomes in Past 12 Months, by Service Branch

2 or more sex partners Sex with a new partner without a condom High risk for HIV
Total 15.9% 33.2% 17.7%
Air Force Reserve 12.3% 26.3% 14.6%
Air National Guard 11.7% 28.8% 13.7%
Army Reserve 14.5% 32.9% 16.5%
Army National Guard 18.3% 35.6% 19.8%
Marine Corps Reserve 24.1% 36.6% 24.9%
Navy Reserve 13.5% 33.8% 15.9%
Coast Guard Reserve 7.9% 32.0% 10.9%

The HRBS found that 1.9 percent (CI: 1.6–2.1) of reservists reported a sexually transmitted infection (STI) in the past 12 months The HRBS defined service members at high risk for human immunodeficiency virus (HIV) infection to include men who had sex with one or more men in the past 12 months, service members who had vaginal or anal sex with more than one partner in the past 12 months, and service members who had an STI in the past 12 months. The survey found that 17.7 percent (CI: 16.7–18.7) were at high risk for HIV.

Among all respondents, 2.5 percent (CI: 2.0–2.9) reported causing or having an unintended pregnancy in the past year. Women (3.2 percent, CI: 2.5–3.9) were more likely to report this than men (2.3 percent, CI: 1.8–2.7). This difference is probably a result of men having incomplete information about the unintended pregnancies. The percentage of women reservists who reported experiencing an unintended pregnancy was lower than among U.S. women of reproductive age (4.5 percent, CI: 4.1–4.9).[1]

Contraceptive Use

In 2016, DoD issued a memorandum (DHA-IPM 16-003) establishing comprehensive standards of care regarding methods of contraception and counseling on methods of contraception. These standards adopt the practice recommendations of the Centers for Disease Control and Prevention (CDC) as the clinical practice guidelines for the military. This section focuses on service members' contraceptive use in the past 12 months at the time of their most-recent vaginal sex and at the time they experienced or caused an unintended pregnancy.

The most commonly used methods among HRBS respondents were condoms and birth control pills (Table 1). Long-acting contraception, such as an intrauterine device (IUD), has been associated with substantially lower unintended pregnancy rates. Long-acting methods are more effective, in part, because they do not require users to remember to use them or to use them correctly, as do some other methods. The most commonly used long-acting method was an IUD.

Table 1. Method of Contraception Used During Most-Recent Vaginal Sex in Past 12 Months

Method of Contraception Percentage Reporting Use
Highly effective methods
Male sterilization (vasectomy) 8.5 (CI: 8.0–8.9)
IUD 9.6 (CI: 9.0–10.3)
Female sterilization (e.g., tubal ligation, hysterectomy) 6.3 (CI: 5.8–6.7)
Contraceptive implant (e.g., Implanon) 3.4 (CI: 2.9–3.8)
Other methods
Condom 23.6 (CI: 22.5–24.6)
Birth control pill 17.8 (CI: 16.9–18.8)
Birth control shots, patch, contraceptive ring, or diaphragm 4.7 (CI: 4.1–5.2)
Some other method 4.8 (CI: 4.3–5.3)
No contraception or not applicable
Did not use any form of birth control 19.1 (CI: 18.2–20.0)
No vaginal sex in past 12 months 15.0 (CI: 14.1–15.9)
I/my partner was trying to get pregnant 6.1 (CI: 5.6–6.6)
I/my partner was already pregnant 2.9 (CI: 2.5–3.3)

NOTE: Unless indicating no vaginal sex in the past 12 months, current pregnancy, or trying to get pregnant, respondents could endorse more than one method.

The HP2020 target for the proportion of women 15 to 44 years of age at risk of unintended pregnancy who used (or whose partners used) contraception at most-recent sexual intercourse is 91.6 percent. The most-recent civilian estimate available, based on 2015–2017 data from the National Survey of Family Growth, is 79.6 percent (CI: 76.7-82.2). The HRBS found that among service women 17 to 44 years of age at risk of unintended pregnancy, 73.8 percent (CI: 71.4–76.1) used contraception at most-recent vaginal sex.

HP2020 has a goal that 69.3 percent of women 20 to 44 years of age use a most effective or moderately effective method of contraception (sterilization or use of a contraceptive implant, IUD, birth control pills/shots/patch/ring, or a diaphragm). Data from the National Survey of Family Growth indicate that between 2015 and 2017, among all U.S. women ages 20–44 who were not already pregnant or trying to become pregnant, 60.2 percent (CI: 57.4–63.0) used a most effective or moderately effective method of contraception. The HRBS found that among servicewomen 20 to 44 years of age, 60.3 percent (CI: 58.1–62.6) used such a method at their most-recent vaginal sex in the past 12 months.

Deployment-Related Unintended Pregnancy, Contraceptive Access, and Counseling

An unintended pregnancy while deployed presents challenges for servicewomen and operational difficulties that can be a threat to force lethality and readiness. The 2016 National Defense Authorization Act required that servicewomen have access to comprehensive counseling on the full range of contraceptive methods at medical visits predeployment and during deployment. The 2017 National Defense Authorization Act directed that information be obtained on the experiences of service members in accessing family planning services and counseling. DoD also requires that contraceptive counseling be delivered at annual physical health assessments, as well as at predeployment and during-deployment health care visits.

The HRBS found that 0.02 percent (CI: 0.00–0.05) of service members experienced an unintended pregnancy during a past-year deployment. Overall, 33.4 percent (CI: 29.3–37.5) of women and 15.2 percent (CI: 13.1–17.3) of men reported receiving contraceptive counseling prior to deployment. Prior to deployment, 82.3 percent (CI: 77.1–87.6) of women and 12.2 percent (CI: 7.2–17.1) of men reported that they were able to get or refill their preferred birth control method. During deployment, 73.7 percent (CI: 66.5–80.9) of women and 14.0 percent (CI: 8.2–19.8) of men reported that they were able to get or refill their preferred birth control.

HIV Testing

The CDC recommends annual testing for HIV among those at high risk and suggests that men who have sex with men consider testing every three to six months. DoD requires HIV screening at least every two years, and an HIV test result within the past 24 months must be on file for a service member to deploy.

The HRBS found that 71.4 percent (CI: 70.2–72.5) of service members reported being tested for HIV in the past 12 months, and 38.5 percent (CI: 37.3–39.6) reported being tested in the past six months. Among personnel at high risk for HIV, 79.1 percent (CI: 76.3–81.9) were tested within the past 12 months. Among men who reported having sex with men, 84.2 percent (CI: 77.8–90.6) reported having an HIV test in the past 12 months, with 67.3 percent (CI: 59.4–75.3) reporting such a test in the past six months. The HP2020 goal is for at least 68.4 percent of men who have sex with men to have annual HIV testing.

Comparisons with the Active Component

To compare HRBS results for the active and reserve components, RAND researchers constructed regression models that controlled for demographic characteristics of the respondents. Significant differences that they identified for reservists relative to active component members included

  • lower likelihood of multiple sex partners, sex with a new partner without a condom, STI, and high risk for HIV in the past year
  • overall, a lower likelihood of using a highly effective contraceptive method at most-recent vaginal sex
  • lower likelihood of HIV testing in the past 12 months.

Conclusions and Policy Implications

Substantial proportions of service members engage in each of several sexual risk behaviors, including sex with multiple partners and, especially, sex with a new partner without use of a condom. DoD, the services, and the Coast Guard should ensure that condoms are easily available to service members regardless of location and at no or reduced costs and should consider implementing regular testing for STIs.

DoD, the services, and the Coast Guard should consider expanding efforts to provide contraceptive counseling to men. The National Survey of Family Growth indicates that 60 percent of men could benefit from planning services, with the highest need among men 20 to 29 years of age, but only 10 percent receive counseling about contraception.[2] Research is ongoing to develop effective contraceptive counseling strategies that target men. Such strategies include counseling men on condom use and how to support their partners in using other methods.

DoD, the services, and the Coast Guard should seek to increase the consistent and effective use of contraception. Under the new contraceptive guidelines adopted by DoD, IUDs and implants are to be considered first-line methods of contraception. Providers and service members, however, might need additional training and education about the benefits of the most effective contraceptive methods, with the caveat that these methods might not be appropriate for all women.

Finally, DoD, the services, and the Coast Guard could increase annual testing rates for HIV infection among those at high risk through better screening during the annual personal health assessment. Although the current form for the personal health assessment asks pertinent questions, it is not clear whether information on various contributors to risk is combined to detect those in the highest risk category, nor is it clear whether certain risks (e.g., men who have sex with men) or combinations of risks should consistently trigger more frequent (annual or biannual) testing for HIV infection.


  • [1] L. B. Finer and M. R. Zolna, "Declines in Unintended Pregnancy in the United States, 2008–2011," New England Journal of Medicine, Vol. 374, No. 9, March 3, 2016, pp. 843–852.
  • [2] A. V. Marcell, S. E. Gibbs, I. Choiryyah, F. L. Sonenstein, N. M. Astone, J. H. Pleck, and J. K. Dariotis, "National Needs of Family Planning Among U.S. Men Aged 15 to 44 Years," American Journal of Public Health, Vol. 106, No. 4, April 2016, pp. 733–739.
  • [3] CIs provide a range in which the true population value is expected to fall. They account for sampling variability when calculating point estimates but do not account for problems with question wording, response bias, or other methodological issues that, if present in the HRBS, might bias point estimates.

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