Furthermore, expression of FAAH is decreased in the first-trimester placenta, extra-villous trophoblast columns, villous cytotrophoblasts, syncytiotrophoblasts, and macrophages; tissues where increased FAAH expression could normally be acting to protect the growing embryo from the detrimental effects of AEA [52,58] and can result in elevated AEA levels in pregnancy that may result in miscarriage. This evidence concerns the gene FAAH and spontaneous abortion.