However, a notable finding was that the four women who experienced spontaneous miscarriage showed a smaller increase in DAO enzyme activity during pregnancy (20.2, 21.4, 23.2, and 30.8 U/mL) compared to the rest of the women, all of whom had DAO levels above 54 U/mL at weeks 12–14 of gestation. This evidence concerns the gene DAO and Miscarriage.