The specific aim of our pilot study was to determine the effect of low-dose aspirin (ASA-81 mg) on cellular (ED1 + -Fn) and total fibronectin (FN) concentration in patients at risk for pregnancy induced hypertension (PIH). Fibronectin, a glycoprotein, is functionally a diverse adhesive glycoprotein found in plasma and connective tissue. Immunohistochemical analysis of human tissues suggest that ED1 + -Fn protein is almost exclusively localized to the endothelium of blood vessels in healthy nonpregnant adults. Measurement of plasma fibronectin levels appear to be a sensitive indicator for the diagnosis of incipient pre-eclampsia in normotensive women at high risk, and secondly it may be a useful biological gauge to monitor those who would be treated with low-dose ASA. The temporal relationship of the rise in fibronectin levels to the onset of symptoms has suggested that vascular endothelial cell damage would be the earliest pathologic process in patients who develop pre-eclampsia. Approximately 87 samples yielded data for 25 patients who were treated with ASA daily and who were prospectively observed for pre-eclampsia. After written consent patients at risk for PIH were randomized in a double-blind fashion to ASA-81 mg or to a placebo tablet. Treatment was instituted at ≥ 12 weeks and after a baseline ED1 + -Fn and total FN concentrations were obtained. Thereafter serum samples were obtained every 2 weeks and at delivery. Patients who were only exposed to the ASA were assayed for its effect on vascular ED1 + and total FN, and incidence of pre-eclampsia. The maternal ages between the PIH group vs the normotensive group were 23.25 ± 2.4 (mean ± SE, n = 24) and 20.5 ± 1.45 (p = 0.28) respectively. Seven of 24 patients (29.2%) developed pre-eclampsia of variable severities. The neonatal gestational ages of the infants whose mothers developed PIH were 39.74 ± 0.44 wks vs 37.58 ± 0.9 wks (p = 0.348) of the normotensive group. The neonatal birthweights of the PIH group were 3453.0 ± 190.6 Kg vs 3165.3 ± 162.03 Kg respectively and not statistically significant.We conclude from our pilot study that although statistically there were no significant differences between the PIH and the normotensive groups in their ASA levels, a trend is present suggesting that with higher serum salicylate levels pre-eclampsia may be ameliorated and/or prevented in patients who are compliant. In addition, it appears that low-dose aspirin has no effect on vascular or total fibronectin.