Plasma concentrations of the circulating adhesion molecules ICAM-1 (CD54), VCAM-1 (CD106) were determined in 31 women with pre-eclampsia, 9 women with HELLP syndrome, and 13 women with transient pregnancy induced hypertension (PIH). Data were compared with a control group of 157 healthy pregnant women of the same gestational age. Furthermore, concentrations of circulating E-selectin (CD62E), P-selectin (CD62P), and PECAM-1 (CD31) were determined in a subpopulation of 17 women with pre-eclampsia. Plasma concentrations of circulating ICAM-1, VCAM-1, E-selectin, and PECAM-1 were significantly elevated in women with pre-eclampsia compared to healthy control pregnant women. Circulating ICAM-1 and VCAM-1 levels were also significantly elevated in the pre-eclampsia group compared to women with PIH. Concentrations of circulating P-selectin varied strongly in all experimental groups (SD>> 70% of the mean), most likely reflecting various degrees of thrombocyte degranulation in the individual samples. Finally, longitudinal profiles of cICAM-1 and cVCAM-1 concentrations were determined in 123 healthy pregnant women between the 16th and the 42nd week of gestation. This analysis identified cICAM-1 and cVCAM-1 as tightly regulated plasma parameters that varied in a small concentration range. Concentrations of cICAM-1 and cVCAM-1 did not vary during pregnancy and the determined concentrations corresponded to the reported reference levels of nonpregnant individuals.