Infants diagnosed with drug withdrawal symptoms at birth, also known as neonatal abstinence syndrome (NAS), are nearly two and a half times as likely to be readmitted to the hospital in the first month after being discharged compared with full-term infants born without complications, according to new Vanderbilt research released today in the journal Hospital Pediatrics.

Drug withdrawal symptoms can occur shortly after birth in infants exposed, while in the womb, to narcotic pain relievers (or opioids) such as hydrocodone. Compared to other infants, those with drug withdrawal are more likely to experience respiratory complications, feeding difficulty, seizures and to have low birth weight.

The study, Risk of Hospital Readmission Among Infants with Neonatal Abstinence Syndrome, is the most recent in an ongoing series of studies by Vanderbilt researchers that delve into the far-reaching implications, short-term and long-term, of drug exposure and withdrawal in newborns. Their previous research showed rates of NAS grew by nearly fivefold in the past decade across the United States. Still, little is known about infants with NAS after their initial hospitalization following birth.

In this latest study, the researchers sought to determine if infants with NAS are at an increased risk for hospital readmission within 30 days from discharge compared with uncomplicated term and late preterm newborns.

"The recent rise of neonatal abstinence syndrome led to efforts in many hospital systems to improve hospital care being delivered to infants with the syndrome. Our findings suggest that these improvements need to extend beyond the initial birth hospitalization to ensure a safe discharge home," said lead investigator Stephen Patrick, M.D., MPH, MS, assistant professor of Pediatrics and Health Policy in the Division of Neonatology at Monroe Carell Jr. Children's Hospital at Vanderbilt.

For their analysis, the researchers examined hospital discharge data for 2006-2009 from the New York State Inpatient Database (SID) and also looked at data for live births from the New York Department of Health. During that time period there were 700,613 uncomplicated term births (at least 38 weeks gestation) and 51,748 late preterm births (born between 33 and 36 weeks gestation). Of those births, 1,643 infants were diagnosed with NAS.

The most common cause for readmission among infants with NAS was withdrawal, whereas the preterm newborns were most commonly readmitted for jaundice.

Patrick said future research and state-level policies should investigate means to mitigate the risk of hospital readmission for infants with NAS.

"As state and federal policymakers work towards strategies to improve outcomes for women with substance use disorder and their infants, it will be important to ensure that families are supported during the critical transition from hospital to home to limit the risk of hospital readmission. The findings of our study suggest that some families may benefit from additional post-discharge resources."