DIFFERENCES IN HOSPITAL LENGTH OF STAY BETWEEN NEONATES EXPOSED TO BUPRENORPHINE VERSUS METHADONE IN UTERO

Abstract

BACKGROUND: Opioid dependence affects up to 30% of pregnancies at our institution and treatment of neonatal abstinence syndrome (NAS) is the leading cause for admission to the NICU. Decreasing the length of hospital stay for these neonates may be beneficial to families as well as to the allocation of hospital resources. OBJECTIVE(S): To characterise the length of stay in hospital and NAS treatment parameters for neonates following in utero exposure to buprenor-phine, methadone, or to non-buprenorphine, non-methadone opioids. DESIGN/METHODS: A retrospective chart review was conducted of 180 mother infant dyads born between 1 January 2012 and 31 December 2014 with in utero exposure to buprenorphine (n=60), methadone (n=60), or to non-buprenorphine, non-methadone opioids (n=60). Exclusion criteria included major congenital abnormalities, significant metabolic or genetic conditions, gestational age less than 37 weeks, and neonates born to mothers with severe pre-eclampsia. The primary outcome was neonatal length of stay in hospital. Secondary outcomes included the number of days of treatment of NAS with morphine, day of life of initiation of treatment with morphine, and the need for adjuvant treatment with phenobarbital. RESULT(S): The length of stay in hospital for neonates with in utero exposure to methadone was 14.5 days (95% CI 11.9-17.1) and for buprenorphine was 8.7 days (95% CI 7.3 to 10.1), a decrease of 5.8 days (95% CI 6.1-8.5 days) for buprenorphine exposure in utero compared to methadone (p = 0.001). For neonates requiring treatment for NAS, those with in utero exposure to buprenorphine required 6.1 (95% CI 2.5 to 9.7) fewer days of treatment with morphine then those exposed to methadone (p < 0.0005). There were no statistically significant differences in day of life of initiation of morphine therapy for each of the study groups. The proportion of neonates requiring adjuvant therapy with phenobarbital was statistically significantly higher in neonates exposed to methadone in utero than either buprenorphine or illicit opioids (p < 0.0005). CONCLUSION(S): Retrospective data suggests that maternal buprenor-phine use results in shorter length of stay in hospital, fewer days of treatment with morphine for NAS, and less use of phenobarbital in neonates exposed in utero than maternal methadone use. This suggests, in conjunction with previous larger prospective studies conducted in the US, that Ontario provincial guidelines should be updated to recommend buprenor-phine first line for replacement therapy in pregnancy.