Plasma anandamide and related n-acylethanolamide levels are not elevated in pregnancies complicated by hyperemesis gravidarum.

OBJECTIVES: Cannabinoids are effective antiemetics and the "endogenous cannabinoids" (endocannabinoids) are thought to modulate emesis in both humans and animal models. Endocannabinoids, their receptors and their metabolising enzymes are present in peripheral blood and a reduction in blood endocannabinoid concentration has been observed in individuals with excessive nausea and vomiting following parabolic flight manoeuvres. We tested the hypothesis that plasma endocannabinoid levels are similarly perturbed in women with hyperemesis gravidarum (HG), a condition where the aetiopathogenesis is still unknown, compared to normal pregnant controls.
METHODS: Plasma N-arachidonoylethanolamine (anandamide), N-oleoylethanolamide and N-palmitoylethanolamide were quantified in women with HG (n = 15) and matched normal pregnant controls (n = 30) using UHPLC-ESI-MS/MS utilising an isotope dilution method and selective ion monitoring.
RESULTS: No significant differences in anandamide, oleoylethanolamide and palmitoylethanolamide levels were observed between the two groups. There were no significant correlations between these endocannabinoids and plasma haematocrit and serum urea or sodium concentrations.
CONCLUSIONS: These results would suggest that either the circulating endocannabinoids quantified may not be key modulating factors in HG or that the expected endocannabinoid system response to the stress induced by nausea and vomiting of early pregnancy remain unchanged in women with HG.