title: The preterm prediction study: elevated cervical ferritin levels at 22 to 24 weeks of gestation are associated with spontaneous preterm delivery in asymptomatic women.
abstract: OBJECTIVE
  Low serum ferritin levels correlate with low iron stores, whereas high levels are associated with an acute-phase reaction. Our objective was to determine whether elevated levels of ferritin in the genital tract may be a potent marker to identify patients at risk for spontaneous preterm delivery.
  
  
  METHODS
  We performed a nested case-control study involving 182 women who had spontaneous preterm delivery and 182 term control subjects matched for race, parity, and recruitment center, and selected from 2929 women enrolled in the Preterm Prediction Study of the National Institute of Child Health and Development Maternal-Fetal Medicine Units Network. Cervical fluid ferritin was measured by use of radioimmunoassay.
  
  
  RESULTS
  Cervical ferritin levels were significantly higher in women who subsequently had spontaneous early preterm delivery (<32 weeks, mean +/- SD, 37.7 +/- 31.1 vs 21.5 +/- 24.1 ng/mL, P =.002; and <35 weeks, 43.2 +/- 62.7 vs 28.2 +/- 36.7 ng/mL, P =.004) than in term controls. A cervical ferritin of >75th percentile in the controls (>35.5 ng/mL) was found in 52.9% (9/17) of the women delivered <29 weeks vs 17.7% (3/17) of the controls (odds ratio [OR] 5.3 [95% CI 1.1-25.2]) and in 43.5% (20/46) of the women delivered <32 weeks versus 10.9% (5/46) of the controls (OR 6.3, 95% CI 2.1-18.9). Cervical ferritin levels had a weaker association with spontaneous preterm delivery <35 weeks (OR 2.8 [95% CI 1.5-5.1]) and <37 weeks (OR 1.6, 95% CI 1.0-2.5]). Cervical ferritin levels correlated significantly with cervical lactoferrin, interleukin-6 (IL-6), and defensin levels.
  
  
  CONCLUSIONS
  Elevated cervical ferritin levels at 22 to 24 weeks of gestation in asymptomatic women are associated with subsequent spontaneous preterm birth. The strong correlation of cervical ferritin with other inflammatory markers provides support for the hypothesis of infection as a mediator of preterm delivery.
authors.affiliation: National Institute of Child Health and Human Development, Maternal-Fetal Medicine Units Network, USA. ramsey_patrick@hotmail.com
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Ramsey
authors.forename: Tsunenobu
authors.initials: T
authors.lastname: Tamura
authors.forename: Robert L
authors.initials: RL
authors.lastname: Goldenberg
authors.forename: Brian M
authors.initials: BM
authors.lastname: Mercer
authors.forename: Jay D
authors.initials: JD
authors.lastname: Iams
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Meis
authors.forename: Atef H
authors.initials: AH
authors.lastname: Moawad
authors.forename: Anita
authors.initials: A
authors.lastname: Das
authors.forename: J Peter
authors.initials: JP
authors.lastname: Van Dorsten
authors.forename: Steve N
authors.initials: SN
authors.lastname: Caritis
authors.forename: Gary
authors.initials: G
authors.lastname: Thurnau
authors.forename: Mitchell P
authors.initials: MP
authors.lastname: Dombrowski
authors.forename: Menachem
authors.initials: M
authors.lastname: Miodovnik
mesh_terms: D000328:Adult; D015415:Biomarkers; D016022:Case-Control Studies; D002584:Cervix Uteri / Q000378:metabolism*; D005260:Female; D005293:Ferritins / Q000378:metabolism*; D005544:Forecasting; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012016:Reference Values
chemical_list: D015415:Biomarkers; D005293:Ferritins