Breaking research in The Journal of Applied Laboratory Medicine shows that the fentanyl in epidurals can pass on to babies during labor. While the infants in this study did not experience adverse effects from this fentanyl transfer, this information is crucial to ensuring that new mothers don’t get falsely accused of fentanyl abuse, which can have dire social repercussions for mother and child.
From 1992 to 2012, the proportion of pregnant women admitted to substance abuse treatment facilities who reported a history of prescription opioid abuse increased from 2% to 28%. This alarming rise has led to a parallel increase in hospitals drug testing mothers and their newborns for opioids, which helps ensure that babies exposed to opioids in utero get prompt treatment for withdrawal symptoms. While some hospitals only drug test mothers and newborns if they suspect the mother of drug abuse, a number of hospitals have begun to test all mothers and babies to prevent discrimination against women from disadvantaged demographics. As these universal drug screening programs become more common, it is critical that laboratory professionals and clinicians have the information they need to interpret drug test results correctly. False positives can have serious consequences—particularly in states like Alabama, where drug use during pregnancy is criminalized and mothers can lose custody of their children and get sent to prison because of it.
Since fentanyl is usually included in epidurals, a team of researchers led by Athena K. Petrides, PhD, of Brigham and Women’s Hospital in Boston, set out to determine whether getting an epidural during labor impacts urine drug test results in newborns. To do this, the researchers performed drug testing on 96 urine samples from newborns whose mothers had no history of fentanyl drug abuse, and 82 of whom had received fentanyl epidurals during labor. One-third of the babies whose mothers received fentanyl epidurals (24 infants total) tested positive for the drug, while all 14 newborns whose mothers did not receive fentanyl epidurals tested negative.
Among the women who received fentanyl epidurals, the researchers found that the likelihood of fentanyl passing on to their babies correlated with the duration and cumulative dose of the epidural. Mothers who received fentanyl for less than 5 hours at a cumulative dose of <100 µg did not have children who tested positive for fentanyl. In contrast, mothers treated for more than 10 hours with a cumulative dose of >100 µg had children with positive fentanyl tests.
“The most important clinical implication of these findings is that a positive neonatal urine fentanyl test result cannot and should not be used to identify fentanyl drug abuse in mothers who receive fentanyl-containing labor analgesia,” said Petrides. “Clinicians should interpret positive neonatal fentanyl results in the context of medications administered during labor and delivery. Fentanyl testing on other specimen types, such as meconium and/or cord tissue, should be considered when evaluating prolonged fetal exposure during gestation.”
