Baby Aspirin and Fertility: Can This OTC Medication Help You Get Pregnant?

Infertility is a medical condition that can cause significant stress. It’s defined as the inability to get pregnant after having unprotected sex for 1 year. 

And it's fairly common. In the U.S., 19% of women are unable to get pregnant after trying for 1 year. Luckily, many people can overcome infertility with treatment, including certain medications, and medical procedures like intrauterine insemination (IUI) and in vitro fertilization (IVF). 

When you think of fertility medications, you may not think of the common over-the-counter (OTC) medication aspirin. But some research suggests that low-dose aspirin (known as “baby aspirin”) may help with infertility in certain people. 

So, how effective is low-dose aspirin for fertility? And is it recommended?

What’s baby aspirin?

Aspirin is in a group of medications called non-steroidal anti-inflammatory drugs (NSAIDs). It’s commonly used to treat pain, fever, and inflammation. It does this by blocking two proteins — cyclooxygenase-1 and -2 (COX-1 and COX-2) — that make a group of chemicals called prostaglandins. Prostaglandins can cause your body temperature to rise, along with pain and inflammation.

At low doses, aspirin can help prevent blood clots. Low-dose aspirin (81mg) is commonly referred to as baby aspirin. It works by preventing platelets from clumping together. Platelets are blood cells that join together to form clots and stop bleeding. Baby aspirin is beneficial for some people because some serious medical events (like heart attacks and strokes) occur due to blood clots. For example, baby aspirin can help prevent another heart attack in people who’ve already had one. 

Can baby aspirin help with fertility?

It’s possible, but it probably only helps in certain situations. Below, we’ll discuss what we know about baby aspirin and fertility. This includes chances of becoming pregnant or having a miscarriage. We’ll also cover baby aspirin use in IVF.

Chance of becoming pregnant

A 2014 study of over 1000 people looked at the effects of taking baby aspirin (81 mg) before and during pregnancy. The study was called the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial. 

The researchers wanted to know if baby aspirin made live birth (having your baby born alive) more likely in people with previous miscarriages (loss of a pregnancy). The study looked at two groups of people between the ages of 18 to 40 years old:

1. Women who had a miscarriage within the past year, and before the 20th week of pregnancy

2. Women who’ve had one to two miscarriages at any point in their life, and any point during pregnancy

According to the study results, baby aspirin only had a positive effect in the first group of women. This was the women who had a miscarriage in the past year (before the 20th week of pregnancy). In this group, the study found that baby aspirin raised the likelihood of getting pregnant. And this led to a higher rate of live births. 

There was no effect on the second group of women. This was the group with one to two miscarriages at any point in their life and at any point during their previous pregnancies.

Risk of miscarriage

The EAGeR study didn’t show that baby aspirin lowered the risk of miscarriage.

However, a separate study reexamined the EAGeR study and found different results. These researchers found that study participants who took baby aspirin consistently (at least 4 days per week) experienced fewer miscarriages. 

And another study found that women who previously had at least one late miscarriage (after the 13th week of pregnancy) had a greater chance of live birth when taking aspirin 75 mg. But aspirin didn’t have any effect on participants who had multiple miscarriages in the first half of their pregnancy. These results may indicate that blood clots are a more likely cause of late miscarriages, and aspirin may be able to help prevent this.

IVF outcomes

IVF is a medical treatment that can help you become pregnant. It involves several steps, including the retrieval of an egg from a woman’s body. The egg is then combined with sperm in a laboratory, which may form an embryo. When an embryo is formed, it’s returned to a woman’s body with the goal of becoming pregnant.

IVF involves a lot of medications. Whether baby aspirin should be one of these medications is unclear. Current research has mixed results. For example, one review of 13 randomized controlled trials (RCTs) —the best kind of study to look for cause-and-effect — looked at whether low-dose aspirin (between 80 to 100 mg) improved IVF outcomes. This includes the chance of becoming pregnant and having a live birth. The review found that low-dose aspirin didn’t improve IVF outcomes. But the researchers noted that many of the studies were low quality.

A different review of 13 RCTs suggested that low-dose aspirin (between 75 to 100 mg) may make pregnancy with IVF more likely. But the number of live births wasn't higher. A smaller RCT of 60 participants found that taking aspirin 100 mg during frozen embryo transfer resulted in a greater chance of becoming pregnant. In this study, aspirin 100 mg was also linked a lower rate of miscarriage and more live births. 

How might baby aspirin work for fertility?

It’s not entirely known how baby aspirin works for fertility. 

One possible explanation is that inflammation may contribute to infertility, and aspirin lowers inflammation in the body. 

Additionally, aspirin may improve blood flow to important reproductive organs: the ovaries and uterus. And since aspirin also prevents blood clots at low doses, it may improve pregnancy outcomes by preventing clots in women who would’ve otherwise experienced one.

What dose of aspirin is best for fertility?

The dose of aspirin that’s best for fertility isn’t known. The studies discussed above used doses between 75 mg to 100 mg. This is a lower dose than what’s used to treat fever, inflammation, and pain. But it's similar to what’s used in heart attack and stroke prevention (81 mg). 

Risks of baby aspirin while pregnant

Baby aspirin is generally considered safe during pregnancy. But there are some risks to be aware of. The biggest potential risk of aspirin during pregnancy is that it raises your chances of bleeding. But this is rare.

Overall, low-dose aspirin isn’t known to cause harm to the mother or baby when taken during pregnancy. The FDA warns against NSAID use at 20 weeks of pregnancy or later, as NSAIDs (besides low-dose aspirin) can affect an unborn baby's kidneys, lungs, and heart. Baby aspirin (81 mg) isn’t included in this recommendation. 

So what’s the verdict? Should I take baby aspirin for fertility?

The American College of Obstetricians and Gynecologist (ACOG) doesn’t currently recommend baby aspirin to prevent miscarriage or improve pregnancy outcomes. But always talk to your healthcare provider if you have questions about baby aspirin in pregnancy. They can help discuss the potential risks and benefits with you. And even though aspirin is available OTC, don’t start taking it without talking to your healthcare provider first. 

It’s important to note that baby aspirin is strongly recommended to help prevent preeclampsia in people who are at high risk of developing it during pregnancy. Preeclampsia is pregnancy-induced high blood pressure. Your healthcare provider can help you figure out if you’re considered high risk for developing preeclampsia. This includes people with a history of preeclampsia. It also includes people who are having twins, or who have certain medical conditions like diabetes and kidney disease.

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Written by:

Daisy Chau, PharmD

Daisy Chau, PharmD, is the drug information pharmacist manager at GoodRx. She is licensed in California and has more than 6 years of experience working as a pharmacist in drug information.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

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