title: Peripheral natural killer cell activity as a predictor of recurrent pregnancy loss: a large cohort study.
abstract: OBJECTIVE
  To determine the predictive value of preconceptional peripheral blood natural killer (pNK) cell activity in patients with recurrent pregnancy loss (RPL).
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  University department.
  
  
  METHODS
  A total of 552 patients with a history of two to six consecutive miscarriages.
  
  
  METHODS
  None.
  
  
  METHODS
  The predictive value of preconceptional pNK cell activity for subsequent miscarriage was analyzed using multivariable logistic regression analysis, with age, number of previous miscarriages, and presence/absence of previous live births and bed rest as covariates.
  
  
  RESULTS
  Age and number of previous miscarriages, but not high pNK cell activity, were found to be independent risk factors for a subsequent miscarriage. No effect of bed rest and previous live birth on the likelihood of live birth was observed (odds ratios 1.28 [95% confidence interval 0.81-2.02] and 0.91 [0.52-1.59], respectively).
  
  
  CONCLUSIONS
  Elevated pNK cell activity was found to not be an independent risk factor for subsequent miscarriage. Clinicians should not measure the plasma NK activity as a systematic recurrent pregnancy loss examination, because its clinical significance is yet to be established.
authors.affiliation: Department of Obstetrics and Gynecology, Nagoya City University, Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Kinue
authors.initials: K
authors.lastname: Katano
authors.forename: Sadao
authors.initials: S
authors.lastname: Suzuki
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Ozaki
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Suzumori
authors.forename: Tamao
authors.initials: T
authors.lastname: Kitaori
authors.forename: Mayumi
authors.initials: M
authors.lastname: Sugiura-Ogasawara
mesh_terms: D000026:Abortion, Habitual / Q000453:epidemiology* / Q000473:pathology*; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D007694:Killer Cells, Natural / Q000473:pathology*; D050498:Live Birth / Q000453:epidemiology*; D011247:Pregnancy; D015995:Prevalence; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D055815:Young Adult
keywords: Recurrent pregnancy loss; cohort study; natural killer cell activity; predictor