['Adenosine is an important metabolic modulator and adenosine concentrations are affected by sympathetic nerve stimulation and cytokine production. Since hyperemesis gravidarum is characterized by overactivation of sympathetic nerves and enhanced production of tumor necrosis factor (TNF)-alpha, plasma adenosine concentrations may be altered. The present study evaluated plasma adenosine concentrations and their relation with norepinephrine and TNF-alpha concentrations in hyperemesis gravidarum.', 'Plasma concentrations of adenosine, norepinephrine, and TNF-alpha were measured in 34 healthy nonpregnant women, and 34 women with hyperemesis gravidarum and normal pregnancies, matched for age, parity and gestational week. The relationships between plasma adenosine, and norepinephrine and TNF-alpha concentrations in hyperemesis gravidarum were evaluated.', 'Mean plasma adenosine, norepinephrine, and TNF-alpha concentrations were significantly increased in women with hyperemesis gravidarum compared to those in nonpregnant and normal pregnant women (p<0.05). The increase in plasma adenosine concentrations correlated with the increase of norepinephrine and TNF-alpha in hyperemesis gravidarum (r=0.50, p<0.05 and r=0.43, p<0.05, respectively).'] Do plasma adenosine concentrations increase in women with hyperemesis gravidarum?