Healthy pregnancy hub

Naproxen (Aleve®)

Last Update: 02 Apr 2025

Welcome to our fact sheet on naproxen during pregnancy and breastfeeding/ chestfeeding. This information is based on available published literature. It should not take the place of medical care and advice from your healthcare provider.

The HEALTHY PREGNANCY HUB team is collaborating with MotherToBaby to share information on this topic. The original version is available here (January 2024).

Serene, our chatbot, can also answer your questions about medications during pregnancy.

Please note that this fact sheet is based on United States information and has been adapted for Canada, with a review by our Canadian experts. Minor differences may exist between the two countries. Always consult your healthcare professional for information tailored to your situation.

1. What is naproxen? 

Naproxen is a medication that has been used to treat pain and fever. It belongs to the class of medication called non-steroidal anti-inflammatory drugs (NSAIDs). Some brand names for naproxen include Aflaxen®, Aleve®, Anaprox®, Flanax®, Naprelan®, Naprosyn® and Menstridol®. 

The U.S. Food and Drug Administration (FDA) states that pregnant individuals should not use NSAIDs after week 20 of pregnancy unless it is specifically recommended by their healthcare provider. 

2. What are the risks according to research?

I take naproxen. Can it make it harder for me to get pregnant? 

Some studies suggest that using naproxen and other NSAIDs might make it harder to get pregnant. This may be more likely when NSAIDs are used often or over a long period of time. 

Does taking naproxen increase the chance for miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons. Some studies have suggested that taking naproxen may increase the chance of miscarriage. As there can be many causes of miscarriage, it is hard to know if a medication, the medical condition, or other factors are the cause of a miscarriage. 

Does taking naproxen increase the chance of birth defects?

Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Studies do not agree if naproxen does or does not increase birth defects. 

Results from a few large studies on NSAIDs, including naproxen, did not show an increased chance of birth defects. Another study looking at 23 pregnancies exposed to naproxen did not find an increased chance of birth defects. 

However, some studies have reported a small increased chance for heart defects when both naproxen and other NSAIDs are used in early pregnancy. An association with cleft lip and palate (an opening in the lip and / or the roof of the mouth) has also been reported, but has not been proven. It is not known if naproxen was the cause of the birth defects in these studies, or if they were due to other factors such as the medical conditions being treated. 

Does taking naproxen in pregnancy increase the chance of other pregnancy-related problems? 

Naproxen should only be used under a healthcare provider’s watch, particularly in the 2nd and 3rd trimesters. Your healthcare providers can closely monitor your pregnancy if you need to use naproxen during your pregnancy. 

One study found that using naproxen during the first trimester increases the chance of the baby being smaller than expected (small for gestational age). 

Using an NSAID in the 2nd half of pregnancy might lower the amount of amniotic fluid (liquid that surrounds the fetus in the uterus). If there is not enough amniotic fluid (called oligohydramnios) other problems could happen for the fetus, such as damage to the kidneys, poor lung development, joint contractures (joints become stiff or unable to move), or even death. In some cases, oligohydramnios requires an early delivery through labor induction (when the healthcare provider uses a medication to start labor early) or c-section. 

Naproxen use later in pregnancy might also cause narrowing of blood vessels in the fetus. 

Does taking naproxen in pregnancy affect future behavior or learning for the child? 

This is not known for a number of reasons. It is difficult to connect later learning problems to one exposure during pregnancy. There is also no study that checks on later learning with naproxen use only in a pregnancy. Studies that have been done on this topic for NSAIDs in general do not agree if there is or is not a higher chance for learning or attention problems. Studies that have suggested a possible association have study design limitations that do not allow us to know if this finding was linked to the medication or other factors, such as the reason the person took an NSAID. 

3. Breastfeeding/ chestfeeding while taking naproxen

Naproxen passes into breast milk/ chest milk in small amounts. Using naproxen is not expected to be harmful to most breastfeeding/ chestfeeding babies. There is one report of blood-related health problems in an infant who was exposed to naproxen and another medication through milk. It is not known if the reported health problems were due to the naproxen, another medication, or other factors. If you suspect the baby has any symptoms (vomiting, diarrhea, bleeding, trouble with feeding, or trouble with weight gain) contact the child’s healthcare provider. Naproxen stays in milk longer than other NSAIDs. NSAIDs that leave the body quicker may be preferred for breastfeeding/ chestfeeding. Be sure talk to your healthcare provider about all your breastfeeding/ chestfeeding questions. 

4. Fathers and sperm donors

If a male takes naproxen, could it affect fertility or increase the chance of birth defects? 

It is not known if naproxen could affect a male’s fertility (ability to get a partner pregnant) or increase the chance of birth defects above the background risk. In general, exposures that fathers and sperm donors have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures here.  

Key points

  • Naproxen (Aleve®) is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain and fever.
  • It is generally recommended to avoid NSAIDs after the 20th week of pregnancy unless prescribed by a healthcare professional, as they can affect the amount of amniotic fluid and the baby’s development.
  • Some studies suggest that naproxen may make it more difficult to conceive and slightly increase the risk of miscarriage, although other factors may also play a role.
  • Using naproxen in early pregnancy may be linked to a small risk of birth defects, but study results are conflicting.
  • Naproxen passes into breast/ chest milk in small amounts, but it stays in the body longer than some other NSAIDs.
  • Consult your healthcare provider before taking naproxen during pregnancy, especially after 20 weeks.

References

Please click here for references. 

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HEALTHY PREGNANCY HUB provides a source of information validated by health professionals; however, this information is provided for informational purposes only and should not replace professional advice. Medical standards and practices evolve as new data becomes available, so it is imperative to consult your doctor or a qualified health professional for any questions or concerns regarding your health without delay or omission. It is the responsibility of your treating physician or any other health professional, based on their independent experience and knowledge of the patient, to determine the best way to evaluate and treat you.

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While consulting symptoms or other medical information on our platform may guide your discussions with your healthcare professional, this information should not be used to make a medical diagnosis or determine treatment. Before making changes to your supplement or medication regimen, please discuss with your medical team or contact 811 (Canada) to ensure the relevance of these changes to your individual situation.

Credits
MotherToBaby
Organization of Teratology Information Specialists (OTIS)
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Émy Roberge
Centre hospitalier universitaire Sainte-Justine
Anne-Sophie Otis
Centre Hospitalier Sainte-Justine

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