Genevieve Dsouza1, Rita Agarwal1
1) United States
Neonatal abstinence syndrome (NAS) is a postnatal drug withdrawal syndrome in newborns caused primarily by in utero exposure to opioids (both prescription or drugs of abuse). In the United States, the incidence of NAS increased 383% during 2000–2012.
We are reporting on an ex 34 week 2 kg infant born to a mother with a history of severe Osteogenesis Imperfecta (OI) and chronic pain. Mother was taking methadone 15mg TID during the pregnancy for her chronic pain and as needed Hydrocodone/Acetaminophen (weaned from a higher dose of 100 mg/day earlier in pregnancy to attempt to limit fetal exposure). Father reported fetal ultrasounds showing limb length less than expected for gestational age with no evidence of in utero rib and limb fractures. Subsequent Xrays showed a femur fracture that was healing.
Methadone is a long acting opioid that crosses the placenta, but has a 5-fold decrease in plasma levels in cord blood due to placental metabolism. The half-life of methadone in the neonate is also prolonged to approximately 32 hours hence withdrawal symptoms may not appear for 24-48 hrs.
Methadone may be transferred in maternal breast milk at a variable rate, although literature suggests an average of 3% of the maternal dose. Hence the infant may not demonstrate evidence of NAS due to the methadone secreted in breastmilk.
This infant continued on breastmilk hence did not exhibit any evidence of withdrawal while hospitalized. She did not receive any additional opioids for her femur fracture and received occasional acetaminophen for pain. We recommended that in the future when ready to wean off breastmilk, she wean off slowly to prevent withdrawal in infant.
We advised parents to watch for sudden changes in infants consumption of of breastmilk (and thus small but steady methadone) intake, drowsiness, dilated pupils or other withdrawal symptoms.
