Neonatal opioid withdrawal syndrome (NOWS) is common due to the current opioid addiction epidemic. The incidence of infant opioid withdrawal has grown rapidly in many countries over the last decade, nearly a fivefold increase, presenting significant health and early brain development concerns.

The rise in prenatal exposure to opioids reflects increasing prescription opioid use as well as the presence of both illegal opiates and opioid-substitution therapies.

The incidence of NOWS has increased, with the costs of treatment in the United States reaching approximately $1.5 billion in 2015. Opioid abuse in pregnant women presents additional risks for the fetus and newborn.

Opioid use during pregnancy, whether prescribed or illicit, can be associated with negative pregnancy and infant outcomes, including prematurity, low birth weight, increased risk of spontaneous abortion, sudden infant death syndrome, and infant neurobehavioral abnormalities. Infants who are at high risk for experiencing symptoms of abstinence or withdrawal may require assessment and treatment.

About 50% to 80% of opioid-exposed infants have required medication to manage their withdrawal symptoms, including irritability, trouble eating and sleeping, diarrhea, and muscle rigidity, which usually appear two to three days after birth.

Naltrexone, buprenorphine, and methadone are three medications approved by the Food and Drug Administration to treat opioid use disorder. Buprenorphine is a newer treatment for maternal opioid addiction and appears to result in a milder withdrawal syndrome than methadone.

However, a recent study led by researchers at Boston Medical Center showed that infants of mothers taking naltrexone during pregnancy had shorter hospital stays than infants of mothers who took buprenorphine during pregnancy.

The researchers followed mother-infant dyads during their pregnancies and after delivery at one academic medical center between 2017 and 2019. Six of the mothers were taking naltrexone to treat their opioid use disorder before and during their pregnancies, and 12 were taking buprenorphine.

The two groups were monitored and compared based on participants' opioid use via urine toxicology reports, provider reports during pregnancy and six months post-delivery, delivery outcomes, gestational age, birth weight, APGAR scores, NICU admission, and NOWS outcomes (diagnosis, pharmacologic treatment, total hospital length of stay). Maternal demographics were also compared between all participants.

The infants born to women taking naltrexone showed no withdrawal symptoms during their initial hospitalization, compared to 92% of infants born to women taking buprenorphine. Of infants with withdrawal symptoms, 46% required medication.

Another important finding in the study was that women taking naltrexone received prenatal care later during their pregnancies than women taking buprenorphine, suggesting that patients and/or providers are not clear on its safety during pregnancy.

According to Elisha Wachman, MD, a neonatologist at Boston Medical College, the preliminary study outcomes are promising and support the need for a larger study examining the long-term maternal and child safety and efficacy outcomes of naltrexone during pregnancy.