January 9, 2015 — The FDA has issued a Safety Communication to announce that a review of a dozen studies has found inconclusive evidence linking the use of common painkillers during pregnancy with birth defects.
The FDA looked at recent studies that found evidence of the following risks:
- Non-steroidal anti-inflammatory drugs (NSAIDs) and a 7-fold increased risk of miscarriage in the first half of pregnancy.
- Opioid use during the first trimester and a doubled increased risk of birth defects of the brain, spine, and spinal cord (neural tube defects)
- Acetaminophen use at any time during pregnancy and an increased risk of attention-deficit hyperactivity disorder (ADHD).
After reviewing the studies, the FDA found serious problems with the way all of the studies were designed. They warned women to “carefully consider” the use of painkillers during pregnancy, but made no changes to recommendations.
The FDA warned:
“We found all of the studies we reviewed to have potential limitations in their designs; sometimes the accumulated studies on a topic contained conflicting results that prevented us from drawing reliable conclusions.”
NSAIDs and Miscarriage
Five studies have investigated the link between NSAIDs and miscarriage, including three studies involving 100,000 pregnancies that found a 7-fold increased risk. However, the FDA found serious limitations in the study methodology. For example, the studies did not investigate whether the NSAIDs were used before or after the miscarriage.
Opioids and Brain, Spine, and Spinal Cord Defects
The FDA looked at two studies involving 28,000 women who were interviewed about their use of opioid painkillers during pregnancy. In both studies, researchers found a 2- to 2.2-fold increased risk of birth defects in the brain, spine, and spinal cord. However, the FDA was concerned that the use of interviews may have biased the results, especially if women who had a baby with a birth defect were more likely to remember using medications during pregnancy.