A CLINICAL-TRIAL OF A SLOW-RELEASE FORMULATION OF ACETYLSALICYLIC-ACID IN PATIENTS AT RISK FOR PREECLAMPSIA

The formation of thromboxane A2 (TXA2) in maternal and foetal cord ser um was measured at birth in eight control patients and in 13 patients taking 100 mg of a slow-release formulation of acetylsalicylic acid. T he serum concentrations of TXB2 (a stable end product of TXA2 hydrolys is) in both maternal and cord serum from patients who ingested the ace tylsalicylic acid formulation were significantly lower (P < 0.01) than those in control subjects. Acetylsalicylic acid was not detected (< 3 0 ng ml-1) in maternal plasma from six mothers and in cord plasma from seven foetuses in the acetylsalicylic acid-treated group. The mean co rd to maternal plasma concentration ratios for detectable acetylsalicy lic acid and salicylate were 0.62 +/- 0.19 (s.d.) (n = 6) and 0.84 +/- 0.16 (n = 13), respectively. We conclude that low doses of acetylsali cylic acid given in a slow-release form to mothers during pregnancy ca use depression of TXA2 formation in the foetal blood.