Medium-dose intravenous immunoglobulin therapy for women with six or more recurrent miscarriages.

This study aimed to evaluate changes in natural killer (NK) cell activity and the percentage of monocytes in women with recurrent miscarriage who received medium-dose intravenous immunoglobulin (IVIg) therapy. Fourteen women with a history of six or more recurrent miscarriages of unexplained etiology received 60-g IVIg therapy (20 g daily, for three days) during early gestation. NK cell activity in the peripheral blood decreased to 12% one week after therapy compared with before therapy (median, 22%, P < 0.001) and the percentage of monocytes increased from 5.2% to 7.5% (P < 0.005). Four pregnancies ended in live births of healthy neonates, whereas the other ten pregnancies ended in miscarriages. Excluding one miscarriage with a chromosomal abnormality, the live birth rate was 30.8% (4/13). The rate of reduction of NK cell activity in the success group (-58.8%) tended to be greater than that in the failure group (-14.8%, P = 0.057).