Anandamide (AEA) and 2-arachidonoylglycerol (2-AG) were the first endocannabinoids to be characterized, that bind two G protein-coupled receptors, CB1 and CB2. AEA synthesized by multiple pathways, including NAPE-specific phospholipase D (NAPE-PLD) and degraded by the fatty acid amide hydrolase (FAAH). AEA levels are critical in regulating embryo development and the ‘‘window’’ of implantation. We examined the expression of nape-pld mRNA, CB1 and FAAH in human placenta hypothesizing that their altered signaling may contribute to spontaneous miscarriage. First trimester placentas from women with spontaneous miscarriage (group 1) were matched with placentas from women who underwent termination (group 2). Nape-pld expression was analyzed by RT-PCR; CB1...