Using Aspirin in Pregnancy to Prevent Preeclampsia

This article should not be taken as medical advice. You should always talk to your provider before starting a new medication, especially during pregnancy. 

Pregnancy is an exciting time, but a lot of questions about prenatal health arise while navigating new territories. It’s important to be cautious about what you put into your body during pregnancy and there are some general recommendations on what to avoid, but some over-the-counter medications are a gray area.

One medication that some healthcare providers recommend during pregnancy is aspirin. This may come as a surprise, but aspirin used during pregnancy is intended for one specific reason – to prevent preeclampsia.

Let’s explore how aspirin may help prevent preeclampsia, as well as the potential risks of using it during pregnancy.

Understanding Preeclampsia

The main use of aspirin during pregnancy is to prevent preeclampsia – the medical term for those with high blood pressure and protein in urine during pregnancy. It affects between 2%-10% of pregnancies globally. 

High blood pressure and hypertension are fairly common, and those with preeclampsia are typically able to have healthy pregnancies by taking steps to regulate blood pressure. 

Symptoms of preeclampsia include:

• Vomiting or nausea
• Persistent headache
• Difficulty breathing
• Pain in the upper stomach
• Swelling in the hands or face
• Vision changes including seeing spots or blurry vision

In some cases, preeclampsia can develop into eclampsia, a potentially life-threatening medical emergency that can cause seizures, blood clotting issues, stroke, and kidney and liver abnormalities.

It can also lead to low birth weight and premature birth in babies. In the United States, about one out of every five medically induced premature births is in pregnancies with preeclampsia. 

People at a high or moderate risk of preeclampsia include those with:

• A history of preeclampsia
• Chronic kidney disease
• Autoimmune diseases such as lupus
• Type 1 or type 2 diabetes
• Chronic hypertension (high blood pressure)
• Family history of preeclampsia
• Pregnant with multiples
• BMI over 30
• IVF pregnancies
• Pregnancy over the age of 35

In certain places, especially the United States, there are other socio-economic factors that can increase the risk of developing preeclampsia, like race, environmental stress and access to healthcare.

The Benefits of Aspirin During Pregnancy

Although preeclampsia can be managed in most cases, it could lead to pregnancy complication. That’s where aspirin comes in. Low daily aspirin use during pregnancy has been shown to prevent or delay the onset of preeclampsia.

It is most often used in people with a history of early-onset preeclampsia or those who have had preterm deliveries at less than 34 weeks gestation.

How does aspirin help to prevent preeclampsia?

Researchers aren’t sure exactly, but they do have some theories. In addition to being antiinflammatory, aspirin also has antiplatelet properties, meaning it stops blood cells, or platelets, from sticking together and forming blood clots. 

Aspirin also helps to reduce the production of thromboxane A2, a hormone that is believed to increase someone’s risk of preeclampsia. 

Risks of Aspirin Use During Pregnancy

As with any new medication, especially one taken during pregnancy, it’s important to know the potential risks of aspirin. 

Research shows that a daily low dose (81 mg) of aspirin is considered safe during pregnancy. The potential risks are low and are less than the risks of preeclampsia for those with a history of the disorder. Studies have found no increased risk of fetal or neonatal effects in babies who were exposed to aspirin while in utero.

It’s important to note that aspirin should NOT be used for the prevention of early pregnancy loss and is not recommended for prior unexplained stillbirth without having other preeclampsia risk factors.

Certain groups of people should avoid aspirin use in pregnancy:

• Those with an aspirin allergy
• Hypersensitivities to other salicylates
• Hypersensitivity or allergies to NSAIDs (ibuprofen and naproxen)
• People with nasal polyps
• History of gastrointestinal bleeding
• Those with peptic ulcer disease

There are potential risks of regular aspirin use. Consuming aspirin daily for more than five years has been associated with an increased risk of gastrointestinal and cerebral bleeding episodes in non-pregnant individuals. It’s important to note that this was at 300 mg a day which is more than three times the amount recommended in pregnancy. 

How To Use Aspirin During Pregnancy

The recommended daily dose of asprin during pregnancy is 81 mg, which is considered a low dose.

Experts recommend starting daily use at the end of the first trimester, but there is some conflicting information about the best time to start aspirin during pregnancy. 

Generally speaking, it’s recommended to start between 12 and 28 weeks gestation. Some experts claim that it’s best to start before 16 weeks gestation and continue use until delivery.

Certain studies support this claim, finding that significant reductions in severe preeclampsia only occurred in patients who started low-dose aspirin before 16 weeks of gestation. 

Again, there are conflicting studies about whether this greatly impacts the effectiveness of aspirin against preeclampsia. Most providers recommend continuing aspirin use until birth, with little apparent benefits of stopping in the last trimester.

Preeclampsia is a potentially serious medical condition that can affect both the baby and mother. Research shows that aspirin can be effective in reducing the risk of preeclampsia and the potential risks that come with it, with few side effects or risks from the medication itself. 

If you are at risk of preeclampsia and are considering using aspirin during pregnancy, be sure to talk to your medical provider about the potential risks and benefits for your specific needs.