The Use of Aspirin to Prevent Ppregnancy-Induced Hypertension and Lower the Ratio of Thromboxane A₂to Prostcyclin in Relatively High Risk Pregnancies

Abstract

We carried out a prospective, randomized, double-blind, placebo-controlled study to investigate the capacity of aspirin to prevent pregnancy-induced hypertension and to alter prostaglandin metabolism. A total of 791 pregnant women with various risk factors for pre-eclamptic toxemia were screened with use of the rollover test (a comparison of blood pressure before and after the woman rolls from her left side to her back) during week 28 or 29 of gestation. Of 69 women with abnormal results (an increase in blood pressure during the rollover test), 65 entered the study and were treated with a daily dose of either aspirin (100 mg; 34 women) or placebo (31 women) during the third trimester of pregnancy. The number of women in whom pregnancy-induced hypertension developed was significantly lower among the aspirin-treated than among the placebo-treated women (4 [11.8 percent] vs. 11 [35.5 percent]; P = 0.024); the same was true for the incidence of preeclamptic toxemia (1 [2.9 percent] vs 7 [22.6 percent]; P = 0.019). The mean ratio of serum levels of thromboxane A2 to serum levels of prostacyclin metabolites after three weeks of treatment decreased by 34.7 percent in the aspirin-treated group but increased by 51.2 percent in the placebo-treated group. No serious maternal or neonatal side effects of treatment occurred in either group. We conclude that low daily doses of aspirin taken during the third trimester of pregnancy significantly reduce the incidence of pregnancy-induced hypertension and pre-eclamptic toxemia in women at high risk for these disorders, possibly through the correction of an imbalance between levels of thromboxane and prostacyclin.

Early initiation of low-dose aspirin for reduction in preeclampsia risk in high-risk women: a secondary analysis of the MFMU High-Risk Aspirin Study

“…The benefit of LDA may be because of the early improvement in spiral artery remodeling during early placental development, or alternately because of the modulation of the heightened systemic inflammation seen in patients with chronic vascular conditions such as hypertension, which is thought to predispose women to the development of preeclampsia. 6 In pregnant women with CHTN, there is greater reactivity within the platelet thromboxane A2 pathway, 23 a pathway which is modulated by LDA, 24 supporting the biologic plausibility of our findings. The limited number of patients in the early preeclampsia group (21 overall, including nine women with CHTN) may have limited our power to determine whether aspirin was beneficial against this outcome.…”

Endogenous biosynthesis of arachidonic acid epoxides in humans: increased formation in pregnancy-induced hypertension.

“…This condition correlates with their mean arterial pressure, plasma lactate dehydrogenase, and the degree of thrombocytopenia (39). Several small studies, which suggest that pretreatment with aspirin may reduce the incidence of PIH in women at risk of developing the disease (40)(41)(42)(43), also support the possibility that thromboxane formation is of functional importance, perhaps contributing to reduced placental blood flow (22,24).…”

Subarachnoid block for caesarean section in severe preeclampsia

“…Preeclampsia patients may also be on concurrent aspirin prophylaxis, which has been demonstrated to significantly improve the maternal and perinatal outcome in such patients. [48]…”