Which medication is most effective at reducing the risk of preeclampsia in a patient with a history of hypertensive disorders during pregnancy?

Aspirin is recognized as the most effective medication for reducing the risk of preeclampsia, particularly in patients with a history of hypertensive disorders during pregnancy. Studies have shown that low-dose aspirin (typically 81 mg daily) can significantly lower the risk of developing preeclampsia, especially in women who are at high risk due to previous occurrences of hypertensive disorders or other risk factors.

The mechanism behind aspirin's effectiveness in this context is believed to involve its ability to improve placentation by promoting better blood flow to the placenta, which is thought to reduce the likelihood of elevated blood pressure and the subsequent development of preeclampsia. The American College of Obstetricians and Gynecologists recommends the use of low-dose aspirin for women identified as high risk for preeclampsia starting in the late first trimester.

While chlorthalidone is a thiazide diuretic used to manage hypertension, it is not specifically indicated for preventing preeclampsia. Magnesium sulfate is primarily used for the prevention and treatment of seizures in women with preeclampsia or eclampsia, not for prevention of the condition itself. Lisinopril is an antihypertensive medication that is contraindicated during