Prophylaxis with low-dose aspirin has been recommended to prevent preeclampsia, the rationale
being that hypertension and abnormalities of coagulation in this disease are caused in part
by an imbalance between vasodilating and vasoconstricting prostaglandins. Low-dose aspirin
therapy inhibits thromboxane production more than prostacyclin production and therefore
should protect against vasoconstriction and pathologic blood coagulation in the placenta.
Initially, several single-center trials, mostly among women at increased risk for
preeclampsia, demonstrated a substantial reduction in the risk of proteinuric hypertension as
well as reductions in the incidences of preterm birth, infants small for gestational age, and
perinatal death,