Peripheral natural killer cell activity as a predictor of recurrent pregnancy loss a large cohort study

Elevated peripheral blood NK cell activity was found to not be an independent risk factor for subsequent miscarriage.

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Kinue Katano, M.D., Sadao Suzuki, M.D., Yasuhiko Ozaki, M.D., Nobuhiro Suzumori, M.D., Tamao Kitaori, M.D., Mayumi Sugiura-Ogasawara, M.D.

Volume 100, Issue 6, Pages 1629-1634, December 2013



To determine the predictive value of preconceptional peripheral blood natural killer (pNK) cell activity in patients with recurrent pregnancy loss (RPL).


Cohort study.


University department.


A total of 552 patients with a history of two to six consecutive miscarriages.



Main Outcome Measure(s):

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.


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).


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.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders.