Should low-dose Aspirin (acetylsalicylic acid) be used in a subsequent pregnancy if the patient had elevated blood pressure (hypertension) in the third trimester?

From the Guidelines

Low dose aspirin is recommended in subsequent pregnancies for patients who had elevated blood pressure in a previous third trimester, with a typical regimen of 81 mg daily, starting between 12-16 weeks of pregnancy and continuing until delivery (or 36 weeks gestation) 1. The American College of Obstetricians and Gynecologists (ACOG) guideline recommends initiating 81 mg daily aspirin for all pregnant women with chronic hypertension to prevent superimposed preeclampsia, which is relevant to patients with a history of elevated blood pressure in the third trimester 1. This preventive therapy should be initiated early in pregnancy because it works by modifying placental development and reducing the risk of preeclampsia, which is more likely to recur in women with previous hypertensive disorders of pregnancy. Aspirin works by inhibiting thromboxane production while preserving prostacyclin, improving the balance between these vasoactive compounds and promoting better placental perfusion, as supported by the U.S. Preventive Services Task Force recommendation statement 1. Some key points to consider when prescribing low-dose aspirin include:

• Starting dose: 81 mg daily
• Timing: between 12-16 weeks of pregnancy
• Duration: until delivery (or 36 weeks gestation)
• Potential side effects: gastrointestinal irritation, which can be reduced by taking the medication with food
• Contraindications: history of aspirin allergy, bleeding disorders, or active gastric ulcers, which should be discussed with a healthcare provider before starting the medication. Overall, the use of low-dose aspirin in subsequent pregnancies for patients with a history of elevated blood pressure in the third trimester is supported by recent guidelines and studies, including the 2020 study published in the American Journal of Obstetrics and Gynecology 1.

From the FDA Drug Label

If pregnant or breast-feeding ask a health professional before use. it is especially important to use aspirin during the last 3 months of pregnancy unless definitely directed to do so by a doctor because it my cause problems in the unborn child or complications during delivery. The FDA drug label does not answer the question.

From the Research

Low-Dose Aspirin in Subsequent Pregnancy

• If a patient had elevated blood pressure in the third trimester of a previous pregnancy, the use of low-dose aspirin in a subsequent pregnancy may be considered to prevent preeclampsia and related complications 2, 3.
• Studies have shown that low-dose aspirin can reduce the risk of preeclampsia, perinatal mortality, preterm birth, and intrauterine growth restriction in high-risk populations 2, 3.
• The American College of Obstetricians and Gynecologists (ACOG) recommends that women with a history of preeclampsia or other high-risk factors should take low-dose aspirin (81 mg/day) starting at 12-28 weeks of gestation and continuing until delivery 2.

Risks and Benefits

• The use of low-dose aspirin during pregnancy has been associated with a lower risk of serious perinatal outcomes, including preeclampsia, perinatal mortality, and preterm birth 2.
• However, there is also a risk of bleeding complications, such as intracranial hemorrhage, although this is rare 4.
• The benefits of low-dose aspirin in preventing preeclampsia and related complications appear to outweigh the risks in high-risk populations 2, 3.

Timing and Dose

• The optimal timing and dose of low-dose aspirin for preventing preeclampsia and related complications are not well established, but most studies suggest starting at 12-16 weeks of gestation and using a daily dose of 100 mg or more 3.
• Further studies are needed to determine the best approach for individual patients 3.

Blood Pressure Monitoring

• Women with a history of elevated blood pressure in the third trimester of a previous pregnancy should be closely monitored for changes in blood pressure during subsequent pregnancies 5.
• Regular blood pressure checks can help identify women at risk of developing preeclampsia and related complications, allowing for early intervention and prevention 5.