Elevated asymmetric dimethylarginine concentrations precede clinical preeclampsia, but not pregnancies with small-for-gestational-age infants

OBJECTIVE: The purpose of this study was to investigate maternal plasma concentrations of asymmetric dimethylarginine (ADMA) in mid pregnancy and at the time of disease in women who experience preeclampsia, compared with women with uncomplicated pregnancies and women with small-for-gestational-age infants. STUDY DESIGN: Plasma samples were collected at mid-pregnancy and at the time of delivery from 31 women with uncomplicated pregnancies, from 12 women with small-for-gestational-age infants, and from 15 women with preeclampsia. ADMA and L-arginine concentrations were measured using high-pressure liquid chromatography. RESULTS: Maternal ADMA concentrations were elevated at mid pregnancy and remained elevated at delivery in women who later experienced preeclampsia (0.45 +/- 0.09 mu mol/L) compared with women with uncomplicated pregnancies (0.34 +/- 0.08 mu mol/ L; P <.01) and with women with small-for-gestational-age infants (0.33 +/- 0.06 mu mol/ L; P < .01). CONCLUSION: Maternal ADMA concentrations are higher in mid pregnancy in women who experience preeclampsia, compared with women with uncomplicated pregnancies and small-for-gestational-age infants. Elevated ADMA concentration before clinical onset of preeclampsia suggests a role of this nitric oxide synthase inhibitor in the pathophysiologic condition of preeclampsia.