title: The preterm prediction study: risk factors for indicated preterm births. Maternal-Fetal Medicine Units Network of the National Institute of Child Health and Human Development.
abstract: OBJECTIVE
  Preterm births occur for many different reasons. Most efforts to identify risk factors for preterm births either ignore cause and consider preterm births as a single entity or examine risk factors for spontaneous preterm births. We performed this study to examine risk factors for indicated preterm births, which constitute more than one quarter of all preterm births.
  
  
  METHODS
  The study included 2929 women evaluated at 24 weeks' gestation at 10 centers. Information was gathered about demographic factors, socioeconomic status, home and work environments, drug and alcohol use, and medical history. In addition vaginal samples were evaluated for fetal fibronectin and bacterial vaginosis and cervical length was measured by transvaginal ultrasonography. Associations with indicated preterm birth were evaluated by univariate tests and by multivariable analysis with logistic regression.
  
  
  RESULTS
  Of the women studied at 24 weeks' gestation 15.3% were delivered of their infants at <37 weeks' gestation. Of these deliveries, 27.7% were indicated preterm births. Risk factors in the final multivariable model were, in order of decreasing odds ratios, mullerian duct abnormality (odds ratio 7.02), proteinuria at <24 weeks' gestation (odds ratio 5.85), history of chronic hypertension (odds ratio 4.06), history of previous indicated preterm birth (odds ratio 2.79), history of lung disease (odds ratio 2.52), previous spontaneous preterm birth (odds ratio 2.45), age >30 years (odds ratio 2.42), black ethnicity (odds ratio 1.56), and working during pregnancy (odds ratio 1.49). Alcohol use in pregnancy was actually associated with a lower risk of indicated preterm birth (odds ratio 0.35).
  
  
  CONCLUSIONS
  The risk factors found in this analysis tend to be different from those associated with spontaneous preterm birth.
authors.affiliation: Maternal-Fetal Medicine Units Network of the National Institute of Child Health and Human Development, Bethesda, Maryland, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Meis
authors.forename: R L
authors.initials: RL
authors.lastname: Goldenberg
authors.forename: B M
authors.initials: BM
authors.lastname: Mercer
authors.forename: J D
authors.initials: JD
authors.lastname: Iams
authors.forename: A H
authors.initials: AH
authors.lastname: Moawad
authors.forename: M
authors.initials: M
authors.lastname: Miodovnik
authors.forename: M K
authors.initials: MK
authors.lastname: Menard
authors.forename: S N
authors.initials: SN
authors.lastname: Caritis
authors.forename: G R
authors.initials: GR
authors.lastname: Thurnau
authors.forename: S F
authors.initials: SF
authors.lastname: Bottoms
authors.forename: A
authors.initials: A
authors.lastname: Das
authors.forename: J M
authors.initials: JM
authors.lastname: Roberts
authors.forename: D
authors.initials: D
authors.lastname: McNellis
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D007234:Infant, Premature; D008171:Lung Diseases / Q000150:complications; D009095:Mullerian Ducts / Q000002:abnormalities; D007752:Obstetric Labor, Premature; D016017:Odds Ratio; D011247:Pregnancy; D011248:Pregnancy Complications; D011249:Pregnancy Complications, Cardiovascular; D011507:Proteinuria / Q000150:complications; D012044:Regression Analysis; D012307:Risk Factors; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires