Chlamydia trachomatis Infections: Implications for Pregnant Adolescents and Their Infants

Objective: Chlamydia trachomatis infections are common in pregnant adolescents. Previous studies have shown that treating pregnant women of all ages with erythromycin prevents transmission of this infection to their infants. However, there are no published studies on the efficacy of aggressive screening and treatment of C. trachomatis in pregnant adolescents. This study was undertaken to determine if aggressive screening for C. trachomatis in pregnant adolescents and early treatment with erythromycin can prevent complications in their newborn infants. Methods: A group of pregnant adolescents enrolled at Teen Pregnancy Service of Milwaukee was evaluated prospectively for the presence of C. trachomatis infection. Screening was performed during the 1st and 3rd trimesters by enzyme immunoassay. Adolescents with positive enzyme immunoassays for Chlamydia were treated with erythromycin for 10 days. Those with negative enzyme immunoassays were enrolled as controls. All infants born to adolescents in both groups were followed for episodes of conjunctivitis, pneumonia, and wheezing during their 1st year of life. Results: Ninety mother/infant pairs were followed during the study period. Twenty-eight mothers (31%) had positive enzyme assay tests and all received erythromycin therapy. Nasopharyngeal cultures were obtained from 60 (67%) infants; all were negative. There were no significant differences in general characteristics, development of conjunctivitis (relative risk 1.27), wheezing (relative risk 0.91), or pneumonia (relative risk 1.12) between infants born to adolescents in either group. Conclusions: We conclude that aggressive screening and treatment of C. trachomatis infection in pregnant adolescents may prevent complications in their offspring.

hlamydia trachomatis is a common sexually transmitted infection among pregnant adolescents; the infection rate ranges from 14 to 27%. [1][2][3] Infections during pregnancy are often transmitted to the infant at the time of delivery. [4][5][6] Rates of transmission vary from 50 to 75% of infants born to infected mothers. Previous studies in women of all childbearing ages have shown that the use of erythromycin during pregnancy diminishes C. tra-chomatis transmission to the infant and prevents complications such as conjunctivitis and pneumonia. 7'* Adolescents are particularly at risk for poor compliance with prenatal care and medication administration and for reinfection with C. trachomat/S. [9][10][11] There are no studies that have examined the effectiveness of erythromycin during pregnancy in a purely adolescent population.
This prospective cohort study was undertaken to evaluate whether infants born to adolescents treated for C. trachomatis with erythromycin during pregnancy were at increased risk for the complications of wheezing, conjunctivitis, and pneumonia compared with infants born to mothers who were negative for C. trachomatis during pregnancy. Chicago, IL) was performed at intake, 36 weeks gestation, and 6-8 weeks postpartum. A mother was considered C. trachomatis positive if a chlamydial enzyme immunoassay was positive during pregnancy. Adolescents with C. trachomatis were treated within week of testing with erythromycin base, 500 mg t.i.d, for 10 days, and retested within month. C. trachomatis infections detected at any time during pregnancy were also treated with erythromycin at the same dose. Prenatal testing, treatment, and instruction regarding chlamydial infection were provided to all patients by a certified nurse-midwife on a one-to-one basis. A multidisciplinary program supported all pregnant teens throughout pregnancy with prenatal education classes, social worker intervention, nutritional counseling through the Women Infant Children Nutrition Site (WIC), and group counseling sessions at the same site. Sexual partners were referred for treatment. At the time of delivery, all infants received erythromycin ophthalmic ointment prophylaxis. Demographic data and smoking history were obtained from each patient.

SUBJECTS AND METHODS
Infants of both C. trachomatis-positive and -negative mothers were followed prospectively for year for episodes of conjunctivitis, pneumonia, and wheezing. Visits were scheduled monthly for the 1st 6 months of the infant's life and then every other month until the 1st birthday. Conjunctivitis was defined as erythema with drainage of or both eyes. Pneumonia was defined as tales in conjunction with abnormal chest X-ray. Wheezing was defined as tachypnea associated with expiratory wheezes on auscultation. Episodes were identified during either well-baby visits or sick visits at the clinic or emergency department; history of eye drainage or respiratory distress was requested from

RESULTS
One hundred ten mother/infant pairs were enrolled and followed during the study period. Twenty pairs were excluded from the study due to change in care providers and loss of follow-up of the infants. There were no differences in the excluded group and the group studied by race, smoking, age, birth weight, or C. trachomatis status. Twenty-eight mothers were C. trachomatis positive and 62 were C. trachomatis negative. Estimated gestational age at intake was 17.2 weeks (range 10-27 weeks) for C. trachomat/s-positive mothers and 16.9 weeks (range [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] weeks) for C. trachomatis-negative mothers. The demographic characteristics for the 2 groups are summarized in Table 1. There were no significant differences for maternal age, race, birth weight, or history of maternal smoking. Eighty-eight of 90 (98%) mothers were eligible for Medicaid.

DISCUSSION
The literature provides little data on the compliance of treatment of C. trachomatis among pregnant adolescents and the outcome of their infants. Although compliance may be a problem for adolescents, we found that most mothers treated early in their pregnancy for C. trachomatis remained disease-free throughout pregnancy. Infants born to mothers treated for C. trachomatis showed no evidence of nasopharyngeal carriage nor did they have conjunctivitis, pneumonia, or wheezing more frequently than infants born to C. trachomatis-negative mothers.
Adolescents, especially during pregnancy, are at greater risk for C. trachomat# infections than adult women. In our study, 31% of pregnant adolescents had C. trachomatis infection. Earlier studies 1-3 have reported an infection rate between 14 and 27%. In another study conducted in Milwaukee, 11% of pregnant adult women (mean age 24 years) were found to be infected with C. trachomatis. 12 Factors The enzyme immunoassay method was used for the detection of C. trachomatis in the endocervical samples from the pregnant adolescents in this study. This method was selected because it is easy to transport and the results can be obtained within day.
Though culture by McCoy cell has been the gold standard for detection of chlamydial infection, the enzyme immunoassay has been shown to be appropriate for the screening of pregnant women and adolescents. Baselski et al. 13 showed the enzyme immunoassay (Chlamydiazyme TM) to have a sensitivity of 96.3 and a specificity of 92.9% compared with culture in a group of pregnant women. In a study of female adolescents, the enzyme immunoassay demonstrated a sensitivity of 100% and a specificity of 88 %. 14 Th timing of C. trachomatis screening and erythromycin therapy during pregnancy is controversial. Schachter et al. 7 treated pregnant patients at 36 weeks gestation in hopes of allowing a C. trachomat#-free genital tract at the time of delivery. Eight of 152 infants in that study were born while the mother was still taking erythromycin; 2 infants developed C. trachomat# infections. Other studies have examined the efficacy of erythromycin for 15 treatment of C. trachomatis during pregnancy.
However, the efficacy has not been examined in a purely adolescent population.
Compliance, risk-taking behavior, multiple sexual partners, and poor condom use are all factors that may make C. trachomatis treatment in pregnant adolescents problematic. We felt that an aggressive approach to the eradication of C. trachomatis during the entire gestation of an adolescent pregnancy is appropriate. In our study, pregnant adolescents were screened and treated at intake and again at 36 weeks gestation. Those adolescents who were positive for C. trachomatis at intake were aggressively treated and tests of cure were performed 2 weeks after completion of therapy. Although the use of erythromycin during pregnancy has been reported to be associated with poor compliance due to gastrointestinal side effects, 16 the adolescents in our study reported completion of their erythromycin course on their follow-up visits. Early testing of pregnant teens permitted identification and treatment of sexual partners. Any adolescent who reported exposure during pregnancy to C. trachomatis from an infected partner was also retested and treated. In the present study, 82% of mothers treated for C. trachomatis during the early months of pregnancy remained negative throughout the pregnancy. With aggressive management, C. trachomatis was eradicated in an additional 14% of teens prior to delivery. Treatment initiated at detection of C. trachomatis at intake was successful in our study and most adolescents remained negative throughout their pregnancy. Patients negative at intake for C. trachomatis who became infected later in pregnancy were detected at testing at 36 weeks.

INFECTIOUS DISEASES IN OBSTETRICS AND GYNECOLOGY 13
Although current Centers for Disease Control 17 recommendations advise testing and treatment at 36 weeks, our data suggest that evaluation should be done at both the prenatal intake and the 3rd trimester to control chlamydial infection in adolescents.
Another argument may be made to support the recommendation for chlamydial detection early in pregnancy. Recent studies have examined the relationship between C. trachomatis infection and premature labor and low birth weight, ls' 18 Ryan et al. 19 showed birth weights of <2,500 g in 19% of infants of untreated C. trachomatis-positive mothers vs. 11% of treated mothers. Others, 2 however, suspect that mucopurulent cervicitis, unrelated to C. trachomatis infection, may be a predictor of adverse pregnancy outcome. Erythromycin therapy, unrelated to C. trachomatis infection, may also improve birth weights; McCormack et al. 21 showed fewer low-birth-weight infants in a group ofwomen infected with Ureaplasma urealyticum treated with erythromycin during the 3rd trimester. In the present study, birth weights were not significantly different in the 2 groups of patients.
The compliance of the pregnant teens in our study was very good, with most presenting for care by 20 weeks gestation and most receiving [10][11] prenatal visits. Our program offers a multidisciplinary approach to teen pregnancy which includes medical, nutritional, prenatal education, pediatric (for siblings), and social services to the pregnant teen and her children at one inner-city site. Most patients are referred by other adolescents and may partly account for the initiation of care prior to the 3rd trimester. We believe that the compliance of our pregnant adolescents may be better than what could be attained through prenatal care at a site not dedicated to the pregnant teen.
All cultures of infants for C. trachomatis were negative. Cell culture by McCoy cell technique was employed for detection of C. trachomatis in the infants since nonculture techniques have not been well studied in the infant population. Although no cultures in the study infants were positive for C.
trachomatis, cultures obtained in the same manner were positive in another group of infants during the same time period. Because cultures may be somewhat fastidious, infants were followed for symptoms that could be related to C. trachomatis infection. 13 In examining conjunctivitis, pneumonia, and wheezing in the 2 groups, we found no differences in risk between infants born to mothers who were C. trachomatis negative and those born to mothers treated during pregnancy for C. trachomatis. Although C. trachomatis may be implicated in 1/3 of infants with pneumonia, 22 we found no increase in risk for pneumonia between the infants born to infected and noninfected mothers. Although C. trachomatis conjunctivitis has been found as often as 51% of the time in young infants with conjunctivitis, 23 we found no increase in risk for conjunctivitis between infants born to infected and noninfected mothers.
Wheezing following C. trachomat# infection has been reported by several authors. [24][25][26] Chronic C. trachomatis infections in infants have also been reported, some lasting over 2 years. 27 No evidence of increased wheezing or chronic infection was found in infants in the group born to mothers treated for C. trachomatis.
The cost of screening and treatment ($84.00) of pregnant teens is far less than the cost of outpatient and in some cases inpatient care of infants with C. trachomatis pneumonia. If, as suspected, C. trachomatis contributes to long-term chronic respiratory disease in older children, further costs will 28 ensue.

CONCLUSIONS
Our study demonstrates that screening and treatment for C. trachomatis in pregnant adolescents early and throughout pregnancy may be effective in eradicating infection and preventing infectious complications in their offspring. Further studies are needed to investigate the impact that C. trachomatis and erythromycin have on the incidence of low birth weight in adolescent pregnancies. Should the newer one-dose antibiotics such as azithromycin be found to be safe for use during pregnancy, treatment may become less complicated. Programs serving pregnant teens must target C. trachomatis as a common infection and offer early and persistent evaluation and treatment.

ACKNOWLEDGMENTS
We thank Margo Kinservik, P.N.P., and Carmen Otero, P.N.P., for their assistance in obtaining infant cultures and Frances Sommer for assistance in preparation of the manuscript. This project was