SAN FRANCISCO – The good news of a prospective, multicenter study presented at the Pediatric Academic Societies meeting was that neonates who were breastfed were less likely to require neonatal abstinence syndrome (NAS) treatment and displayed milder symptoms.

The study also identified other risk factors associated with the need for NAS treatment and the severity of NAS.

“These findings are important because many of these risk factors are modifiable. Prenatal care providers strive to provide the best treatments for both the mother and the fetus. Our findings regarding the association of NAS with some maternal drug exposures can be shared with opiate-dependent mothers during general counseling about tobacco and illicit use in pregnancy and in counseling about NAS,” explained Megan Stover, MD, a fellow in maternal-fetal medicine and genetics at Tufts Medical Center in Boston.

The current standard of care for opioid-dependent pregnant women is medication-assisted treatment with either methadone or buprenorphine. The intervention can be effective in curbing continued opioid abuse and preventing relapse. However, for many of their unborn children, the damage has already been done.

The scope of the problem in the United States is staggering. Between 2004 and 2013, there was a fourfold to fivefold increase in the rate of admissions to neonatal intensive care units (NICUs) for NAS. “It has been estimated that, every minute in the United States, one neonate will require treatment for NAS,” said Dr. Stover. The glum reality for the Tufts researchers is that 50%-80% of opiate-exposed infants will require treatment for NAS. The aim is to reduce this rate.

Dr. Stover was part of a study conducted at hospitals on the U.S. East Coast that aimed to clarify factors before and after birth that were associated with NAS. The enrolled mothers had been treated during their third trimester or following admission for birth for opioid dependence or had received an opioid for relief of chronic pain. They had given birth to their child at term.

Neonates who were born prematurely or who had comorbidities judged to be significant were not part of the analyses. Of the 306 neonates included, 52% required treatment for NAS and 48% did not. The two groups were similar in age of the mother and for neonatal characteristics of gestational age, sex, ethnicity, and body measurements at birth. The severity of NAS was gauged in two ways. One was the number of days of treatment required to free the neonates from the opioid-induced symptoms, with less than 10 days indicating mild NAS, greater than 30 days indicating severe NAS, and the intervening days indicating moderate NAS. Severe NAS also was indicated by the use of two or more medications.

There was good news. Neonates were significantly less likely to require NAS treatment if they were breastfed exclusively, compared with formula fed babies (15% vs 67%; P less than .0001). NAS was usually mild in breastfed babies and often severe in formula-fed babies (P less than .002).

“Our findings regarding the favorable outcomes seen with breastfeeding support recent research regarding the influence of nonpharmacologic approaches to the prevention and management of NAS, namely that more soothing environments, like those outside the NICU, may be more optimal settings for infants undergoing surveillance for NAS,” said Dr. Stover.

Neonatal treatment was more prevalent for women whose opioid substitution therapy involved methadone (54% vs 28% of untreated neonates; P less than .0001). When therapy used buprenorphine, 62% of the neonates did not display NAS. The drug used for substitution therapy had no effect on the length of treatment of the neonates.

“Our data regarding methadone exposure [versus buprenorphine] adds to a growing literature surrounding more favorable neonatal effects seen with this opiate maintenance agent over methadone,” commented Dr. Stover.

NAS treatment was more prevalent for mothers who smoked during pregnancy, compared with those who did not (76% vs 42%; P equal to .02), and for maternal use of illicit drugs (50% vs 34%; P equal to .002), with no effect on length of neonatal treatment.

Maternal psychiatric diagnosis was associated with neonatal NAS (P equal to .03), as was prescription benzodiazepine use in the third trimester of pregnancy (P equal to .02). Benzodiazepine use did not influence the length of treatment. However, maternal alprazolam use did, as it was associated with more severe NAS (P less than .001). Use of selective serotonin reuptake inhibitor during pregnancy was also associated with more severe NAS (P equal to 0.01).

The researchers are currently sifting through the genetic data gathered in the study. The goal is to combine the clinical and genetic data to create a risk score that will be used to tailor care before birth and in the early weeks following birth.

The study was sponsored by Tufts Medical Center and was funded by National Institute on Drug Abuse. Dr. Stover reported having no relevant financial disclosures.

Breastfeeding among factors that modify neonatal abstinence syndrome