Citing Kidney Risk, FDA Warns Against NSAID Use in Pregnancy

The U.S. Food and Drug Administration (FDA) has recommended against the use of non-steroidal anti-inflammatory drugs (NSAIDs) after 20 weeks of pregnancy due to the risk of fetal kidney dysfunction, which can lead to lower levels of amniotic fluid.

Although it is widely accepted among obstetric and midwifery specialists that NSAIDs should be avoided in pregnancy, some women with chronic inflammatory conditions may be advised to continue taking NSAIDs during pregnancy. The latest recommendations have been released to alert treating medical staff and pregnant women to the newly recognized risks of NSAIDs in pregnancy.

What Are NSAIDs?

Non-steroidal anti-inflammatory drugs (NSAIDs) are a group of medications that commonly treat pain and fever by reducing the body's inflammatory response. 

Common NSAIDs include aspirin, ibuprofen, diclofenac, or celecoxib, to name a few. The FDA update has a list of NSAIDs available that includes brand names to help you identify which medicines may contain NSAIDs.

What Are the Risks in Pregnancy?

NSAIDs have been shown to cause a rare but serious type of dysfunction of the fetal kidneys. Kidneys are responsible for urine production, which in turn is what creates amniotic fluid. Therefore, if the fetal kidneys are not functioning properly, the result can be a drop in the level of amniotic fluid surrounding the unborn baby.

Very low levels of amniotic fluid are known as oligohydramnios. The American Pregnancy Association explains that amniotic fluid is essential for the unborn baby's muscle development, lung maturation, and digestive system function.

Additionally, the amniotic fluid provides cushioning for the fetus and for the umbilical cord, which provides blood flow from the mother to the fetus. Therefore, inadequate cushioning can cause compression of the umbilical cord and inadequate blood flow to the fetus.

NSAIDs after 30 weeks of gestation may cause early closure of the ductus arteriosus, a vessel connected to the fetal heart. The American Heart Association explains that the fetal heart pumps deoxygenated blood through the ductus arteriosus to be sent back to the placenta for reoxygenation.

After birth, when the baby begins to breathe air and oxygenates blood via the lungs, the ductus arteriosus closes. If it closes prior to birth, then the unborn baby cannot efficiently send blood back to the placenta to pick up fresh oxygen.

What About Before 20 Weeks? 

It is generally considered safest to avoid NSAIDs in pregnancy completely. Some studies suggest NSAID use in early pregnancy, including around the time of conception, can increase the risk of miscarriage.^

Why Has My Doctor Told Me to Take Aspirin?

Dr. Thomas Vaughn of the Texas Fertility Center explains that low dose aspirin can be prescribed from 12 weeks gestation until 34 weeks gestation in pregnancies that are very high risk for pre-eclampsia.

“One of the most common reasons for an obstetrician to prescribe aspirin in pregnancy is to delay the onset of pre-eclampsia in pregnancy in women at high risk for developing it,” Vaughn says.

The latest FDA recommendations specifically exclude low dose (81mg) aspirin that is prescribed for specific medical conditions of pregnancy. Vaughn explains that this dose is much lower than a standard dose of aspirin (325mg) and thus may pose a lower risk.

In addition to aspirin, some women are advised to take NSAIDs in pregnancy due to chronic inflammatory or rheumatic conditions.^ The FDA advises that if this is necessary, then the lowest effective dose should be used for the shortest possible time.

What to Do If You've Taken NSAIDs

If you have taken NSAIDs in pregnancy and they have not been prescribed, avoid taking any more and see your doctor. Kimberly Langdon, MD and retired OBGYN, advises that if you have taken NSAIDs while you are pregnant, it is best to see your doctor. “You may need serial ultrasounds to evaluate for oligohydramnios if it was prolonged use.”

If you are prescribed NSAIDS, you should be monitored closely with regular ultrasound scans to assess amniotic fluid levels. Vaughn explains, “Any women given NSAIDs should be monitored for decreasing amniotic fluid (which is a sign of kidney damage in the...fetus). Fortunately, in some cases...decreasing amniotic fluid thought to be due to the use of NSAIDs appears to be reversible when the medication is discontinued.”

NSAID Alternatives

General aches and pains often occur in pregnancy due to your changing body. Just because NSAIDs are not suitable doesn't mean you have to suffer. Heat packs, acetaminophen, and physical therapy are generally considered safe alternatives in pregnancy.

It is important to remember that every pregnancy is different, and it is vital you seek expert advice from a certified doctor or midwife about your individual situation or if you have any new or intense pain during pregnancy.