Methadone is standard pharmacotherapy for opioid-dependent pregnant women, yet the relationship between maternal methadone dose and neonatal abstinence syndrome (NAS) severity is still unclear. This research evaluated whether quantification of fetal methadone and drug exposure via meconium would reflect maternal dose and predict neonatal outcomes.
Prospective clinical study
An urban drug treatment facility treating pregnant and post-partum women and their children
Forty-nine opioid-dependent pregnant women received 30–110 mg methadone daily.
Maternal methadone dose, infant birth parameters and NAS assessments were extracted from medical records. Thrice-weekly urine specimens were screened for opioids and cocaine. Newborn meconium specimens were quantified for methadone, opioid, cocaine and tobacco biomarkers.
There was no relationship between meconium methadone concentrations, presence of opioids, cocaine and/or tobacco in meconium, maternal methadone dose or NAS severity. Opioid, cocaine and tobacco biomarkers also were found in 36.7, 38.7 and 81.1% of meconium specimens, respectively, and were associated with positive urine specimens in the third trimester. The presence of opioids other than methadone in meconium correlated with increased rates of preterm birth, longer infant hospital stays and decreased maternal time in drug treatment.
Methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) concentrations in meconium did not predict infant birth parameters or NAS severity. Prospective urine testing defined meconium drug detection windows for opiates and cocaine as three months, rather than the currently accepted six months. The presence of opioids in meconium could be used as a biomarker for infants at elevated risk in the newborn period.