The Effects of Prenatal Prescription Medication Exposure on Neonatal Abstinence Syndrome
Background: The increased occurrence of neonatal abstinence syndrome (NAS) is a major public health concern within Canada and the United States. NAS is a drug withdrawal syndrome caused by the abrupt cessation of prolonged prenatal exposure to opioids. Because of the increasing number of infants affected with NAS and subsequent increased utilization of hospital resources for NAS, research to improve NAS definition, measurement, and management is needed. This study aims to describe the presentation of NAS in neonates prenatally exposed to buprenorphine vs. methadone. Methods: We conducted a prospective cohort study of pregnant women with opioid use disorder and their neonates. Women were treated with buprenorphine or methadone based on clinical indicators and patient preference. Neonates were assessed using the 31-item Finnegan scale and scored every four hours, increasing to every two hours if NAS pharmacotherapy was initiated. Differences in NAS symptoms were compared among 34 buprenorphine-exposed neonates and 43 methadone-exposed neonates prior to and following NAS pharmacotherapy initiation were statistically assessed. Individual growth curve models (IGC) were applied to the Finnegan score data, adjusted for confounders, and NAS trajectories were plotted by prenatal exposure to buprenorphine or methadone. Results: Prior to NAS pharmacotherapy initiation, four NAS symptoms were observed significantly more often in buprenorphine exposed neonates compared to methadone exposed neonates: continuous high pitched crying (76.5% vs. 32.6%), hyperactive Moro reflex (47.1% vs. 23.3%), nasal stuffiness (42.4% vs. 15.9%), and loose stools (50.0% vs. 23.3 Furthermore, we were able to successfully apply an IGC approach to modeling change trajectories to repeated Finnegan score data. Differences in NAS progression by prenatal opioid agonist therapy exposure were identified in neonates who required NAS pharmacotherapy. Conclusion: This is one of the first studies to investigate NAS symptom expression by prenatal opioid agonist therapy exposure to buprenorphine and methadone. This study will provide a resource for other researchers to apply these novel procedures which have not been previously used in pediatric research. The findings from this study provide insight into how these two prenatal medications affect NAS symptom expression and NAS progression allowing healthcare professionals to improve NAS definition, measurement, and management.