Maternal serum nitric oxide levels associated with biochemical and clinical parameters in hypertension in pregnancy

Objectives: To measure maternal serum concentrations of total nitrites, as an index of nitric oxide synthesis, in normal and hypertensive pregnant wom en, and to examine the correlation between these concentrations and several variables of clinical interest. Study design: A total of 60 women in four different groups were studied: 10 normotensive pregnant women, 17 pregnant women with preeclampsia, 18 pregnant women with gestational hypertension an d 15 pregnant women with chronic hypertension. Serum nitrite levels were de termined using the Griess reaction after reduction with nitrate reductase. Results: Serum nitrite levels were higher in preeclamptic women (34.1 +/- 1 4 mu mol/l, P=0.04), lower in chronic hypertensive woman (19.56 +/- 6.46 mu mol/l, P = 0.04) and similar in women with gestational hypertension (26.97 +/- 9.44 mu mol/l) in comparison to the control group (25.37 +/- 7.24 mu m ol/l). Serum nitrite levels in preeclamptic women had significant positive correlations with hematocrit, fasting insulinemia, and apolipoprotein B and negative correlations with platelet count, serum phosphorus and glucose:in sulin ratio, Tn pregnant women with chronic hypertension a negative correla tion was found between serum nitrite levels and active partial thromboplast in time. In pregnant women with gestational hypertension, serum nitrite lev els had negative correlations with birthweight and 24-h urine calcium, and positive correlations with mean preeclamptic corspuscular hemoglobin, 24-h urine sodium and maternal age. Conclusions: We suggest that in women with p reclampsia, a higher maternal nitric oxide level may act as a compensatory mechanism against hemoconcentration and platelet. aggregation and that nitr ic oxide production may be related to some metabolic events. In women with gestational hypertension, higher serum nitrite levels may be related to cli nical and biochemical findings common in preeclampsia. In chronic hypertens ion, a lower maternal nitric oxide level is related to the status of coagul ation. We suggest that in women with preclampsia, a higher (C) 1999 Elsevie r Science Ireland Ltd. All rights reserved.