Methadone maintenance therapy during pregnancy is the recommended treatment for opioid use disorder and should be continued at a stable dose. However, regardless of maternal dose stability, neonates are at significant risk of neonatal abstinence syndrome (NAS) due to in utero opioid exposure. MCCQE objectives emphasize anticipatory guidance and appropriate newborn monitoring in substance-exposed pregnancies.

Symptoms of NAS (irritability, tremors, poor feeding, vomiting, diarrhea, seizures) typically begin within 24–72 hours after birth but may be delayed with long-acting opioids such as methadone. Therefore, routine observation in hospital for at least 72 hours is recommended to monitor for withdrawal and initiate supportive or pharmacologic treatment if needed.

Naloxone is contraindicated in opioid-dependent neonates except in life-threatening respiratory depression because it may precipitate severe withdrawal. Stable maternal dosing does not eliminate NAS risk, so early discharge is inappropriate. Breastfeeding is generally encouraged in stable methadone-maintained mothers, as methadone transfer in breast milk is minimal and may reduce withdrawal severity. Continuing methadone during pregnancy is safer than untreated opioid use.