STD Prevalence and Reproductive Health Services for Adolescent Women in Special Settings in Minnesota, 2001

Background: Adolescent females have the highest infection rates of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) of all age-gender groups. In 2000, adolescent females (15-19 years old) in the United States had a reported CT rate of 2,406 per 100,000 persons and a reported GC rate of 715 per 100,000 persons [1]. Although the rates are slightly lower in Minnesota (1,253 per 100,000 for CT; 347 per 100,000 for GC in 2000) [2], sexually transmitted diseases (STDs) such as CT and GC adversely affect thousands of Minnesota adolescents and threaten their reproductive health.

The STD and HIV Section, Minnesota Department of Health through a grant from the Centers for Disease Control (CDC) conducted the following study to assess the prevalence of STDs, pregnancy, and contraceptive use among adolescent women in high-risk settings. These settings include nine urban school-based clinics (SBCs), a suburban juvenile detention center (JDC), and an urban organization serving homeless youth (OSH).

Methods: All adolescent females presenting at the JDC or the OSH during the sampling period were invited to participate in the study. Due to the large volume of visits at the SBCs, study recruitment was limited to sexually active adolescent females presenting for STD testing and/or reproductive health services during the sampling period.

Demographic, behavioral, and reproductive health data were collected by nursing staff. Urine specimens and/or swabs were collected from each participant and were tested for chlamydia and gonorrhea at the MDH Public Health Laboratory using the Abbott LCx nucleic acid amplification test. HIV and pregnancy tests were performed when clinically indicated or upon the participant's request. Pap smears, Syphilis, and Trichomonas tests were only performed at the SBCs. Specimens that were missing, unsatisfactory, or contaminated and specimens yielding indeterminate test results were excluded from analysis.

Results: The study sample included a total of 1,997 participant visits: 1,870 at the SBCs, 92 at the JDC, and 35 at the OSH. The visits represented 1,471 individuals: 1,361 at the SBCs, 80 at the JDC, and 30 at the OSH. The median age was 16-17 years old and ranged from 12 to 21 years. The racial distribution of participants varied by site type (Table 1), but all three sites had a large proportion of non-White participants relative to the overall adolescent population in Minnesota. The large majority of participants were enrolled in school (93%) at the time of study recruitment. Of the 146 participants not enrolled in school, 68% reported completing 12th grade. The large majority of participants at each site reported ever having vaginal sex: 99% at SBC, 98% at JDC, and 94% at OSH. Other self-reported sexual behavior and contraceptive use varied by site (Table 2). Participants at the JDC reported the highest median number of sexual partners in the last three months (2 partners), the lowest percentage of current contraceptive use (9%), and the lowest percentage of condom use during last vaginal sex (15%). Participants at the SBCs had the highest percentage currently using some form of contraception (76%), but only 51% of participants at the SBCs used a condom the last time they had vaginal sex. The most common forms of contraception used at the SBC were the male condom, the birth control pill, and Depo-Provera. Compared with the SBC, the use of Depo-Provera was more common at the JDC. The pill and withdrawal method were used more frequently at the OSH.

A total of 111 participants reported being currently pregnant. By site type, the SBC had the highest proportion of pregnant participants (6%); the proportion was slightly lower at the JDC (3%); and none of the participants at the OSH were pregnant. For all sites combined, Asian/Pacific Islanders had the highest proportion of pregnant participants (13%) followed by American Indian/Alaskan natives (7%) and Blacks (6%). Whites had the lowest proportion (3%).

For all sites combined, 9.7% of participant tests were positive for chlamydia. The site-specific positivity rate for chlamydia ranged from 0% at the OSH to 7.8% at the JDC and 10.0% at the SBCs (Table 3). The chlamydia positivity rate was highest among Blacks (12.6%) and Asian/Pacific Islanders (12.0%). American Indian/Alaskan natives had a slightly lower rate (8.3%) while Whites had the lowest rate overall (6.9%). Participants reporting 3 or more sexual partners in the last three months had the highest positivity rate (19%) compared to those with 2 partners (14.9%), 1 partner (8.7%), and 0 partners (9.7%) in the last three months. The chlamydia positivity rate was also higher among those who did not use a condom during last vaginal sex (12.1%) than among those who did (7.6%). Adolescent women reporting at least one prior pregnancy had a higher rate (12.2%) than those who had never been pregnant (9.0%). The CT positivity rate did not significantly differ by age, ethnicity, current pregnancy status or contraceptive use.

The overall positivity rate for gonorrhea was 2.5%. There were no gonorrhea cases at the JDC or OSH. All 47 cases of GC in this study were diagnosed at the SBCs, yielding a site-specific GC positivity rate of 2.6%. Similar to chlamydia, the gonorrhea positivity rate was highest among Blacks (4.7%). The rate was lower among Whites (1.1%), Asian/Pacific Islanders (0.7%), and persons of Other/multiple races (2.3%). There were no gonorrhea cases among the 35 American Indian/Alaskan natives tested. The GC positivity rate did not significantly differ by self-reported sexual behavior or contraceptive use. Over half (53%) of those testing positive for gonorrhea also tested positive for chlamydia.

A repeat infection was defined as a positive test result > 3 weeks following a previous positive result for the same STD. Thirteen individuals seen at the SBCs had a repeat infection during the nine-month sampling period. No individuals at the JDC or OSH had known repeat infections during the study period. The average time between positive tests was 3 months (range 1 to 10 months).

Comments: Sexually active adolescent females in the urban school-based clinics included in this study were at high risk for STDs. Over ten percent of the adolescents tested positive for gonorrhea or chlamydia. Given the magnitude of asymptomatic infections, routine screening for chlamydia and gonorrhea seems prudent for all sexually active adolescents in this setting, consistent with CDC guidelines and recommendations.

Adolescent females at the urban SBCs had a relatively high gonorrhea-chlamydia co infection rate (53%). According to the Centers for Disease Control & Prevention (CDC), co infection rates of 10-30% of gonococcal infections are high enough to warrant routine dual therapy without testing for chlamydia in that population. During this study, chlamydia tests were simultaneously performed on all GC cases diagnosed at the SBCs and chlamydia treatment was reserved for those who tested CT positive. However, if tests for CT and GC are not done simultaneously, SBCs should consider the implementation of routine dual therapy for confirmed GC cases.

The relatively high proportion of chlamydia infections among females at the suburban JDC underscores the need for STD screening and treatment among females at high risk in areas outside of Minnesota's urban centers.

The findings in this study are subject to at least two limitations. First, the majority of the study participants were sexually active adolescent females seeking reproductive health care. The participants may not be representative of all adolescent females. Second, the behavioral risk data were based on self-reports and may be subject to reporting bias.

[1] STD Surveillance, 2000. Division of STD Prevention. National Center for HIV, STD & TB Prevention. Centers for Disease Control & Prevention. return to text

[2] STD Surveillance, 2000. Minnesota Department of Health. return to text

Table 1. Characteristics of Study Participants by Site Type


Juvenile Detention Center

Homeless Youth Clinic

Median Age

16 yrs

16 yrs (12-18)

17 yrs (14-19)



654 (35%)

70 (77%)

18 (51%)


704 (38%)

7 (8%)

8 (23%)

 Asian/Pacific Islander

302 (16%)

1 (1%)

0 (0%)

 American Indian/Alaskan Native

28 (2%)

11 (12%)

3 (9%)


177 (10%)

2 (2%)

6 (17%)



248 (13%)

3 (3%)

2 (6%)


1620 (87%)

88 (97%)

33 (94%)

Grade in school*


  9 (1%)

5 (6%)

1 (3%)


55 (3%)

3 (3%)

2 (6%)


253 (13%)

11 (12%)

2 (6%)


460 (25%)

31 (34%)

3 (9%)


538 (29%)

26 (29%)

11 (31%)


547 (30%)

14 (16%)

16 (46%)

* For those not enrolled in school, 'Grade' refers to the highest grade completed.
Percent (%) based on the total number of responses which may be less than the total number of study participants (N).

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Table 2. Self-Reported Behaviors of Study Participants by Site Type


Juvenile Detention Center

Homeless Youth Clinic

Ever had vaginal sex




Had > 1 partners in last 3 months
Currently using birth control
Used condom during last vaginal sex
Currently pregnant
Had one or more previous pregnancies

Percent (%) based on the total number of responses which may be less than the total number of study participants (N).

Table 3. Positivity Rates* by Site Type


Juvenile Detention Center

Homeless Youth Clinic


10.0% (n=1784)

7.8% (n=77)

0.0% n=33)

2.6% (n=1778)
0.0% (n=77)
0.0% (n=33)
0.0% (n=146)
0.0% (n=48)
0.0% (n=1)
0.0% (n=111)
7.0% (n=299)
Abnormal Pap+
16.4% (n=615)

*Positivity rate calculated as the number of positive results over total number of test results (n).
+Abnormal Pap smear includes atypical, low-grade, high-grade, and benign results.

This study was supported by the Centers for Disease Control & Prevention under the 2000 grant:
Monitoring STD Prevalence and Reproductive Health Services for Adolescent Women in Special Settings

For questions about this study, please contact Peter Carr of the Epidemiology and Surveillance Unit at (651) 201-5414.

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Updated Tuesday, 16-Nov-2010 12:22:28 CST