title: Spontaneous resolution of asymptomatic Chlamydia trachomatis in pregnancy.
abstract: OBJECTIVE
  We sought to estimate the rate of spontaneous resolution of asymptomatic Chlamydia trachomatis in pregnancy and to evaluate factors associated with its resolution.
  
  
  METHODS
  A cohort of women enrolled in a large multicenter randomized bacterial vaginosis antibiotic trial (metronidazole versus placebo) that, when randomly allocated, had asymptomatic C trachomatis diagnosed by urine ligase chain reaction (from frozen archival specimens) between 16(0/7) and 23(6/7) weeks were included. The urine ligase chain reaction is a highly accurate predictor of genital tract chlamydial infection. A follow-up ligase chain reaction was performed between 24(0/7) and 29(6/7) weeks.
  
  
  RESULTS
  A total of 1,953 women were enrolled in the original antibiotic trial; 1,547 (79%) had ligase chain reaction performed both at randomization and follow-up. Women receiving antibiotics effective against Chlamydia between randomization and follow-up or having symptomatic Chlamydia infection were excluded (26 women). Of the 140 women (9%) who were diagnosed as positive via the initial ligase chain reaction assay, 61 (44%) had spontaneous resolution of Chlamydia by the follow-up ligase chain reaction assay. Factors associated with spontaneous resolution included older age (P = .02), more than 5 weeks from randomization to follow-up (P = .02), and a greater number of lifetime sexual partners (P = .02). Using a logistic regression model, maternal age and a greater-than-5-week follow-up interval remained significant; for every 5-year increase in maternal age, the odds of a positive result on the ligase chain reaction test at follow-up decreased by 40% (odds ratio 0.6; 95% confidence interval 0.4-0.9). Race, substance abuse, parity, and treatment with metronidazole were not associated with spontaneous resolution. Gram stain score and vaginal pH at randomization and follow-up also were not associated.
  
  
  CONCLUSIONS
  The prevalence of asymptomatic C trachomatis in pregnancy was 9%; infection resolved spontaneously in almost half of these women. The association of older age and increasing time interval to spontaneous resolution of Chlamydia is consistent with a host immune-response mechanism.
authors.affiliation: Department of Obstetrics & Gynecology, University of Texas Southwestern Medical Center at Dallas, Texas 75390-9032, USA. Jeanne.Sheffield@utsouthwestern.edu
authors.forename: Jeanne S
authors.initials: JS
authors.lastname: Sheffield
authors.forename: Williams W
authors.initials: WW
authors.lastname: Andrews
authors.forename: Mark A
authors.initials: MA
authors.lastname: Klebanoff
authors.forename: Cora
authors.initials: C
authors.lastname: Macpherson
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Carey
authors.forename: J M
authors.initials: JM
authors.lastname: Ernest
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Wapner
authors.forename: Wayne
authors.initials: W
authors.lastname: Trout
authors.forename: Atef
authors.initials: A
authors.lastname: Moawad
authors.forename: Menachem
authors.initials: M
authors.lastname: Miodovnik
authors.forename: Baha
authors.initials: B
authors.lastname: Sibai
authors.forename: Michael W
authors.initials: MW
authors.lastname: Varner
authors.forename: Steve N
authors.initials: SN
authors.lastname: Caritis
authors.forename: Mitchell
authors.initials: M
authors.lastname: Dombrowski
authors.forename: Oded
authors.initials: O
authors.lastname: Langer
authors.forename: Mary J
authors.initials: MJ
authors.lastname: O'Sullivan
mesh_terms: D000328:Adult; D000890:Anti-Infective Agents / Q000627:therapeutic use; D002690:Chlamydia Infections / Q000150:complications / Q000175:diagnosis*; D002692:Chlamydia trachomatis; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D022521:Ligase Chain Reaction; D008795:Metronidazole / Q000627:therapeutic use; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis*; D012075:Remission, Spontaneous; D016585:Vaginosis, Bacterial / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy
chemical_list: D000890:Anti-Infective Agents; D008795:Metronidazole