Levels of stable metabolites of prostacyclin and thromboxane A2 and their ratio in normotensive and preeclamptic pregnant women during the antepartum and postpartum periods.

OBJECTIVE

To measure the levels of the circulating metabolites of prostacyclin and thromboxane A2 during the antepartum and postpartum periods in severe preeclamptic and eclamptic patients as well as in normotensive pregnant women.

METHODS

6-Keto-prostaglandin F1alpha (6-keto-PGF1alpha) and thromboxane B2 (TxB2) were measured in the plasma of 15 severe preeclamptic, 15 eclamptic, and 15 normotensive pregnant women during the antepartum and postpartum (5th day) periods. At the same time blood pressure measurements were obtained. Kruskal-Wallis, Wilcoxon rank-sum, and Wilcoxon's signed-rank tests were used for statistical analysis.

RESULTS

1. There was no significant difference in the levels of 6-keto-PGF1alpha and TxB2 of the normotensive pregnant women between the antepartum and the postpartum (5th day) periods. 2) In the severe preeclamptic and eclamptic groups, 6-keto-PGF1alpha levels showed significant increase after the delivery (P < 0.01, and P < 0.001, respectively). 3) In the severe preeclamptic and eclamptic groups TxB2 levels showed significant decrease after delivery (P < 0.01, and P < 0.001, respectively). 4) The 6-keto-PGF1alpha/TxB2 ratio both during the antepartum and the postpartum (5th day) periods showed significant differences between the severe preeclamptic and normotensive, and between the eclamptic and normotensive groups (P < 0.001, and P < 0.001 respectively). 5) No correlation was observed between the mean arterial pressure and the antepartum levels of 6-keto-PGF1alpha TxB2 or their ratios.

CONCLUSIONS

Our study was able to demonstrate a significant difference in circulating metabolites of prostacyclin and TxA2 between normotensive pregnant women and those with severe preeclampsia and eclampsia. But no correlation was observed between the blood pressure and the antepartum 6-keto-PGF1alpha, TxB2 levels or their ratios. 6-keto-PGF1alpha levels increased and TxB2 levels decreased in the postpartum period (5th day). However, the 6-keto-PGF1alpha/TxB2 ratio was still low in the severe preeclamptic and eclamptic patients when compared with the control group. This situation shows that the pathophysiologic mechanism does not improve completely within a few days after delivery.