NAIP and spontaneous abortion: The analysis of differences in the level of expression of genes tested in milk stem cells, depending on whether the women had had previous miscarriages, showed that the expression of BIRC2 (p = 0.038), BIRC6 (p = 0.045), and NAIP (p = 0.033) genes is statistically significantly lower in women who experienced miscarriages (Figure 8).