Naproxen in pregnancy

What is that?

Naproxen is a type of pain reliever that your doctor can prescribe. It belongs to a class of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs). This leaflet summarizes the effects of naproxen and other NSAIDs on a baby in the womb.

The use of naproxen during pregnancy is not advised unless prescribed by a doctor, especially if you are 30 weeks or more pregnant. Acetaminophen is generally recommended to control pain or fever during pregnancy. If paracetamol does not control the pain, it is important to ask your doctor for advice before taking naproxen or any other NSAID. Naproxen may be prescribed during pregnancy for some women with certain diseases; women who need to take naproxen after 30 weeks of pregnancy will be monitored by a fetal medicine specialist.

What if I have already taken naproxen during pregnancy?

Taking naproxen before week 30 of pregnancy is unlikely to harm a baby in the womb. However, if you have taken or are taking any medicines, it is always a good idea to tell your doctor that you are pregnant so that we can decide together if you still need any medicines.

If you have taken naproxen after week 30 of pregnancy, it is important that you tell your doctor or midwife as soon as possible.

Can taking naproxen while pregnant cause miscarriage?

It’s not clear whether taking naproxen in early pregnancy could increase the chance of miscarriage. Of the two studies that investigated miscarriage in women taking naproxen, one found a possible link to naproxen use, while one did not. Some studies have also shown that women who take any type of NSAID during pregnancy are more likely to have a miscarriage than women who don’t.

Can taking naproxen while pregnant cause my baby to be born with birth defects?

A baby’s body and most of its internal organs are formed during the first 12 weeks of pregnancy. It is mainly during this time that certain medications are known to cause birth defects.

Numerous studies have investigated the possible links between naproxen intake in the first trimester and birth defects. Overall, current information does not raise the alarm that birth defects are caused by naproxen use in pregnancy, although ongoing research is needed.

What problems can taking naproxen after 30 weeks of pregnancy cause for my baby?

**Premature closure of the ductus arteriosus
**Before birth, a blood vessel in the baby called the ductus arteriosus must remain open to supply the baby in the womb with the mother’s nutrients and oxygen. The ductus arteriosus closes after birth. ;Premature closure of the ductus arteriosus; is the medical term used to describe this blood vessel that closes prematurely.

Taking naproxen or another NSAID after 30 weeks of pregnancy can cause the ductus arteriosus to close while the baby is in the womb. It is important to contact your doctor or midwife immediately if you have taken an NSAID after 30 weeks of pregnancy, especially if you have taken more or more than the recommended dose.

**Persistent Pulmonary Hypertension of the Newborn (PPHN)
**PPHN occurs when a newborn’s lungs don’t adapt to breathing outside the womb. It is thought to be related, in some cases, to premature closure of the ductus arteriosus (see above). PPHN is generally rare but can be serious.

Although two small studies showed a link between PPHN and NSAID use during pregnancy, another larger study did not show a link. More research is needed to evaluate the possibility of PPHN following in utero exposure to NSAIDs and especially naproxen.

Oligohydramnios (reduction of fluid around the baby) Using
naproxen or other NSAIDs after 30 weeks of pregnancy can result in oligohydramnios (where there is too little amniotic fluid in the sac around the baby).

Naproxen should only be taken after week 30 of pregnancy under medical supervision. If you took naproxen after 30 weeks of pregnancy, your obstetrician may want to check your baby (and amniotic fluid levels) using ultrasound.

Can taking naproxen while pregnant cause stillbirth?

No studies have investigated the possibility of stillbirth particularly after the use of naproxen in pregnancy. Two studies of women taking any NSAID during pregnancy show no link with stillbirth. While this is reassuring, more research is needed to confirm these findings and to separately analyze pregnancy outcomes in women taking naproxen.

Can taking naproxen while pregnant cause preterm birth or is my baby small at birth (low birth weight)?

There is no evidence that the use of any NSAID in pregnancy causes premature delivery or low birth weight of the newborn.

Can taking naproxen during pregnancy cause learning or behavioral problems in the baby?

A baby’s brain continues to develop until the end of pregnancy. It is therefore possible that taking certain medicines at any stage of pregnancy could have a lasting effect on the baby’s learning or behaviour.

No studies have evaluated learning and behavior in infants exposed to naproxen in the womb.

Can taking naproxen while pregnant cause other health problems for the baby?


One study found that children whose mothers took naproxen during pregnancy were no more likely to develop asthma by 18 months of age than children not exposed to naproxen.

Will my baby need extra monitoring during pregnancy?

Most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects as part of their routine prenatal care. Taking naproxen before 30 weeks of pregnancy does not normally require additional monitoring of the baby.

If you took naproxen after 30 weeks of pregnancy, extra scans are likely needed to monitor your baby’s well-being. Discuss this with your midwife/midwife.

Are there any risks to my baby if the father took naproxen?

We would not expect any increased risk to your baby if the father took naproxen before or around the time the baby was conceived.

Who can I talk to if I have questions?

If you have any questions about any of the information in this leaflet, please talk to your doctor.

Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.

She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform,

Leave a Reply

Your email address will not be published. Required fields are marked *