The FDA is warning pregnant women to avoid some commonly used pain relievers later in their pregnancy.  

The FDA warns that use of nonsteroidal anti-inflammatory drugs around 20 weeks or later into a pregnancy"may cause rare but serious kidney problems in an unborn baby.” The advisory also says usage can lead to low levels of amniotic fluid surrounding the baby and complications.

Advil, Aleve, Motrin and Celebrex are among the brands included in the warning.

Dr. Mitchell Kramer, chairman of Obstetrics and Gynecology at Huntington Hospital, says he and many obstetricians already tell their patients to avoid these medications.

"When I do my first prenatal care counseling session with a patient, I advise them to avoid those medications from the start,” says Kramer. "Just as a precaution, but I think the fact that the FDA just updated the warning validates the fact that these medications are best avoided in pregnancy all together."

There was already a warning in effect for pregnant women to avoid taking these drugs after about 30 weeks because of the possibility of heart issues in the unborn baby.

The FDA's updated warning requires companies to make changes to labeling. The warning does not apply to Tylenol, acetaminophen or low-dose aspirin.  

Federal regulators said they decided to extend the warning after finding 35 cases of the amniotic fluid problem reported to the FDA.

Click HERE for more info from the FDA.