title: Chlamydia trachomatis C-complex serovars are a risk factor for preterm birth.
abstract: BACKGROUND
  Potential associations between current or previous C. trachomatis infections (general IgG and serovars) and spontaneous preterm birth (PTB) were examined and associations between C. trachomatis infections and previous fertility problems were explored.
  
  
  METHODS
  At week 17, Chlamydia antigen, Chlamydia IgG, Chlamydia complex B, C and GF levels were measured. Spontaneous preterm birth (< 37 completed weeks gestation) was the primary outcome, and secondary outcomes included infertility treatment, subfertility and ectopic pregnancies. Crude and adjusted relative risks (RR) and odds ratios (OR) were estimated by logistic regression.
  
  
  RESULTS
  C. trachomatis C-complex positivity was associated with spontaneous PTB [RR 2.6 (1.1-6.29)] and additionally with a prior history of subfertility [OR 4.4 [2.5-7.7]), infertility treatment [OR 7.2 (4.0-12.8)] and ectopic pregnancy [5.2 (2.2-12.4)].
  
  
  CONCLUSIONS
  A previous infection with C. trachomatis C-complex was associated with an increased risk for spontaneous PTB and may potentially contribute to subfertility, infertility and ectopic pregnancy.
authors.affiliation: NANEA, Department of Epidemiology, Institute of Public Health, University of Aarhus, 8000 Aarhus C, Denmark.
authors.forename: Stine
authors.initials: S
authors.lastname: Hollegaard
authors.forename: Ida
authors.initials: I
authors.lastname: Vogel
authors.forename: Poul
authors.initials: P
authors.lastname: Thorsen
authors.forename: Inge Panum
authors.initials: IP
authors.lastname: Jensen
authors.forename: Carl-Heinrich
authors.initials: CH
authors.lastname: Mordhorst
authors.forename: Bernard
authors.initials: B
authors.lastname: Jeune
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000097:blood / Q000276:immunology; D002690:Chlamydia Infections / Q000150:complications*; D002692:Chlamydia trachomatis / Q000276:immunology*; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000382:microbiology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D011271:Pregnancy, Ectopic / Q000382:microbiology; D047928:Premature Birth / Q000209:etiology* / Q000382:microbiology; D012307:Risk Factors
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial