Episode Details

Episode 167: Aspirin in Pregnancy

Dr. Marquez explains the use of aspirin during pregnancy to prevent preeclampsia. Dr. Arreaza adds comments and questions and clarifies that aspirin is not used for the treatment of preeclampsia.

Written by Verna Marquez, MD, and Hector Arreaza, MD.

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Introduction to the topic: Pregnancy is a special time in a woman’s life, and we want to make sure that both the mother and the baby are safe and healthy. 

1. What is aspirin? Aspirin is one of the most ancient medications in history, it is known as acetyl-salicylic acid (ASA) and it belongs to the family of non-steroidal anti-inflammatory drugs (NSAID), and it is also an anti-platelet, among other properties that may be unknown. 

It is widely used for pain, fever, and inflammation, but due to adverse effects during viral illness (i.e. Reye Syndrome), it is used less frequently during viral infections. 

As we know, aspirin is widely used to treat myocardial infarction and ischemic stroke, and especially for secondary prevention. The use of aspirin for primary prevention of cardiovascular disease has become less popular, but we are going to leave that discussion for another episode because today we will talk about the use of aspirin in pregnancy!

2. Why should we use aspirin in pregnancy?

Low-dose aspirin in pregnancy is most commonly used to prevent or delay the onset of preeclampsia. Aspirin lowers the risk of preeclampsia by 10% and its consequences (such as growth restriction and preterm birth). Several organizations have agreed on the risk factors we will mention briefly. These organizations are ACOG (American College of Obstetricians and Gynecologists), USPSTF (US Preventive Services Task Force), and SMFM (Society for Maternal-Fetal Medicine).

3. Who should we start on aspirin in pregnancy? 

Aspirin is not for every pregnant patient, for example, a healthy nulliparous or any patient who had an uneventful, full-term delivery previously, is considered low risk and should NOT be started on aspirin because there is no benefit in preventing any condition. 

Low-dose aspirin is recommended for women who have at least a high-risk factor because the incidence of preeclampsia is about 8% in these patients. The risk factors are:

•Previous pregnancy with preeclampsia (especially early onset and with an adverse outcome)

•Type 1 or 2 diabetes mellitus.

•Chronic hypertension.

•Multifetal gestation.

•Kidney disease.

•Autoimmune disease with potential vascular complications (antiphospholipid syndrome, systemic lupus erythematosus).

Your patient only needs 1 high-risk factor to be put on aspirin in pregnancy. 

4. What are the moderate risk factors?

A patient needs to have more than 1 moderate risk factor to meet the criteria for prenatal aspirin.

•Nulliparity.

•Obesity (BMI >30).

•Family history of preeclampsia in mother or sister.

•Age ≥35 years.

•Sociodemographic characteristics (Black persons, lower income level [recognizing that these are not biological factors]).

•Personal risk factors (for example, previous pregnancy with low birth weight or small for gestational age newborn, previous adverse pregnancy outcome [such as stillbirth], interval >10 years between pregnancies). However, low-dose ASA prophylaxis is not recommended solely for the indication of