Pre-conceptional natural killer cell activity and percentage as predictors of biochemical pregnancy and spontaneous abortion with normal chromosome karyotype

PROBLEM: The aim of the present study was to determine whether pre-conceptional natural killer (NK) cell activity and percentage are predictive of subsequent spontaneous abortion in women with recurrent spontaneous abortion (RSA). METHOD OF STUDY: Pre-conceptional NK cell activity and percentage in peripheral blood of women who had a history of two or more RSA was prospectively assessed. The Cr-51 release assay and flow cytometric analysis were performed. A total of 113 RSA women were recruited, and 85 conceived later. RESULTS: Pre-conceptional NK cell activity/percentage values in women whose next pregnancies ended in biochemical pregnancy and spontaneous abortion with normal fetal karyotype (n = 17, median 47%/17.1%), but spontaneous abortion with abnormal karyotype (n = 9, 27%/15.7%), were higher than those in live births (n = 59, 33%/13.1%). High values of pre-conceptional NK cell activity ( > 46%; relative risk 3.6, 95%CI 1.6-8.0) and percentage ( > 16.4%; 4.9, 1.7-13.8) were found to predict biochemical pregnancy and spontaneous abortion with normal karyotype in the next pregnancy. CONCLUSION: Pre-conceptional NK cell abnormalities were predictive of spontaneous abortion with normal fetal karyotype.