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Pregnant women treated with buprenorphine for opioid use disorder (OUD) experienced significantly better outcomes for themselves and their infants than women not treated with buprenorphine during pregnancy, based on data from more than 14,000 individuals.

“Opioid use disorder in pregnancy has increased substantially in the United States and is associated with adverse outcomes for both mothers and infants, but at least 50% of pregnant women with OUD nationwide do not receive treatment,” said Sunaya Krishnapura, BA, a medical student at Vanderbilt University, Nashville, Tennessee, in an interview. Krishnapura presented the findings at the Pediatric Academic Societies (PAS) 2025 Meeting.

Krishnapura and colleagues reviewed data from 14,463 mother-child dyads with OUD who were enrolled in Medicaid in Tennessee from 20 weeks estimated gestational age to 6 weeks postpartum. Of these, 7469 mother-child dyads received buprenorphine treatment. The primary maternal outcomes were severe maternal morbidity, intensive care unit admission, and maternal mortality. The primary infant outcomes were preterm birth, neonatal intensive care unit (NICU) admission, and infant mortality.

Overall, women in the nontreatment group were significantly more likely to be non-Hispanic Black individuals compared with those in the treatment group (10% vs 2.1%; P < .001).

In adjusted propensity score analyses, the buprenorphine group had a 5.1% lower risk of adverse pregnancy outcomes overall, including 1.2% and 1.7% lower probability of severe maternal morbidity and infant NICU admission, respectively.

In particular, women treated with buprenorphine had a 5.3% lower probability of preterm birth than those who were not treated, which has significant long-term health implications for the infants, said senior author Stephen Patrick, MD, a professor and chair of the Department of Health Policy and Management at Rollins School of Public Health, Emory University, Atlanta, in a press release.

The probability of preterm birth was 11.7% in the treated group compared with 17.0% in the untreated group.

“Preterm birth is a growing public health issue in the United States, affecting 10.4% of all pregnancies as of 2022, Krishnapura told Medscape Medical News. “Previous studies have demonstrated an association between opioid use disorder during pregnancy and preterm birth, including some reports of preterm birth rates up to 20% in pregnant women with opioid use disorder,” she said.

“What we found most surprising was the benefit buprenorphine treatment provided to newborns,” she noted. “We typically think of buprenorphine providing a significant benefit to pregnant women, and it does; however, we found that treating mothers with buprenorphine is associated with a profound reduction in preterm birth, with odds of preterm birth being reduced by 5%,” she said.

Clinical Implications 

“Since its approval in 2002, buprenorphine has become the dominant medication used to treat opioid use disorder in the United States, in large part because of policy at the state and federal level,” Krishnapura said. Data on the effect of buprenorphine vs no treatment are limited, she said.

However, the current study adds to the available knowledge by showing an association between buprenorphine use in pregnancy and substantial improvements in pregnancy outcomes, specifically a lower probability of severe maternal morbidity, NICU admission, and a more than 5% reduction in preterm birth, Krishnapura told Medscape Medical News.

“While efforts have been made to increase access to buprenorphine 

through state and federal legislation, pregnant women with opioid use disorder continue 

to face significant barriers to access, and our study results highlight the need for policies to expand treatment access in the United States,” she said.

Study limitations included the use of filled prescription records as an indicator of buprenorphine use vs observation of administration, which may have biased the results, she noted.

Other limitations included the focus on only Medicaid enrollees in Tennessee, which may have limited generalizability and the use of propensity scoring, she said.

Looking ahead, “future research should continue to explore the long-term effects of buprenorphine for pregnant women and infants,” said Krishnapura. “Next, even though our study found substantial treatment benefits, it is important to know that there are only three medications used to treat opioid use disorder, and we need substantially more research to discover more highly effective treatments,” she said.

Balancing Risks and Benefits

The treatment of OUD during pregnancy can reduce the many long-term deficits for the children born from these pregnancies, said Martin E. Olsen, MD, a professor in the Department of Obstetrics and Gynecology at East Tennessee State University, Johnson City, Tennessee, in an interview.

“This research can promote dialogue to devise strategies to improve neonatal outcomes,” said Olsen, who was not involved in the study.

The new study “confirms current understanding that treating opioid use disorder in pregnancy is undoubtedly better than failing to treat opioid use disorder in pregnancy,” Olsen said. However, “While treatment of substance use disorder in pregnancy is an improvement over no treatment, many clinicians recognize the long-term consequences of buprenorphine on neonatal abstinence syndrome (NAS) and on fetal development. Clinicians rightly want to ensure that the treatments they prescribe provide more benefits than harm,” he emphasized.

Previous studies showed that 52% of neonates on buprenorphine will experience NAS and that babies with NAS have smaller head circumferences and experience long-term educational deficits, Olsen said. Other data suggest that opioid-exposed newborns who do not have neonatal opioid withdrawal syndrome (NOWS, NAS specifically for opioids) are at an increased risk for mortality, he added.

“Traditional teaching has minimized the effect of buprenorphine dose on neonatal outcome, but a growing body of evidence links lower buprenorphine dosages to lower rates of NOWS and improved neonatal head circumference,” he said.

“Further research on the effect of buprenorphine dose on rates of NAS/NOWS and long-term outcomes such as mortality, educational achievement, childhood weight gain, and brain structure is essential,” Olsen told Medscape Medical News. “Additionally, buprenorphine/naloxone may be a safer therapy than buprenorphine monotherapy in areas with high fentanyl penetration; further research analyzing the safety of buprenorphine/naloxone is needed,” he said.

This study was supported by the National Institute on Child Health and Human 

Development. The researchers had no financial conflicts to disclose. Olsen had no financial conflicts to disclose.