title: Chlamydia trachomatis infection may increase the risk of preeclampsia.
abstract: BACKGROUND
  Although the etiology of preeclampsia is not well understood, it has been suggested that excessive systemic inflammation may lead to oxidative stress, promoting the endothelial dysfunction characteristic of preeclampsia. Few prospective studies have examined the role of infection, an immune system stimulator, as a risk factor for preeclampsia.
  
  
  METHODS
  We conducted a longitudinal study of the relationships between Chlamydia trachomatis (CT), Chlamydophila pneumoniae (CP), cytomegalovirus (CMV), herpes simplex virus (HSV) and preeclampsia among 509 preeclamptic cases and 336 normotensive controls nested within the Danish National Birth Cohort study. Antibodies were analyzed at a first prenatal visit (mean 17.0weeks) and at a late second/third trimester study visit. Prenatal infections were identified as IgG/IgM seroconversion or a fourfold rise in IgG antibody titers. Multiple regression models were adjusted for maternal age, BMI, smoking status, and time between blood draws.
  
  
  RESULTS
  CT infection was associated with preeclampsia (ORadj 1.6, 95% CI 0.7, 3.6), severe preeclampsia (ORadj 1.8, 95% CI 0.6, 5.3), and preeclampsia resulting in preterm birth (ORadj 1.7, 95% CI 0.6-4.9) or birth of a small for gestational age infant (ORadj 2.1, 95% CI 0.6, 7.5), although CT infection was uncommon (n=33, 4.0%) and associations were not statistically significant. CP, CMV, and HSV infection were not associated with preeclampsia.
  
  
  CONCLUSIONS
  Women with serological evidence of prenatal CT infection were more likely to develop preeclampsia, although infection was infrequent and confidence intervals were wide. Studies in populations at higher risk for STIs are needed to corroborate this association.
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States; Magee-Womens Research Institute, Pittsburgh, PA, United States. Electronic address: haggerty@pitt.edu.
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Haggerty
authors.affiliation: Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Inge
authors.initials: I
authors.lastname: Panum
authors.affiliation: Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Soren A
authors.initials: SA
authors.lastname: Uldum
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Debra C
authors.initials: DC
authors.lastname: Bass
authors.affiliation: University of Aarhus, Denmark School of Public Health and the Danish Epidemiology Science Centre, Aarhus, Denmark.
authors.forename: Jorn
authors.initials: J
authors.lastname: Olsen
authors.affiliation: Children's Hospital of Pittsburgh, Pittsburgh, PA, United States; Pediatric Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
authors.forename: Toni
authors.initials: T
authors.lastname: Darville
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Jamie M
authors.initials: JM
authors.lastname: Eastman
authors.affiliation: Magee-Womens Research Institute, Pittsburgh, PA, United States; Magee-Womens Hospital of UPMC, Pittsburgh, PA, United States; Department of Obstetrics, Gynecology & Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Hyagriv N
authors.initials: HN
authors.lastname: Simhan
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States; Magee-Womens Research Institute, Pittsburgh, PA, United States; Magee-Womens Hospital of UPMC, Pittsburgh, PA, United States; Department of Obstetrics, Gynecology & Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: James M
authors.initials: JM
authors.lastname: Roberts
authors.affiliation: University of Texas School of Public Health, Houston, TX, United States.
authors.forename: Roberta B
authors.initials: RB
authors.lastname: Ness
keywords: Chlamydia trachomatis; Chlamydophila pneumoniae; Cytomegalovirus; Herpes simplex virus; Preeclampsia