What is the typical onset time of Neonatal Opioid Withdrawal Syndrome (NOWS) in a pregnant person who uses heroin?

Neonatal Opioid Withdrawal Syndrome (NOWS) typically manifests in newborns exposed to opioids during pregnancy, and the onset of withdrawal symptoms can vary depending on various factors, including the type of opioid used and the timing of the last use before delivery. In the case of heroin, which is a short-acting opioid, the onset of symptoms in the neonate generally occurs between 48 to 72 hours after birth.

This timing is primarily due to the pharmacokinetics of heroin and its metabolites. After exposure during pregnancy, heroin is metabolized rapidly, and withdrawal symptoms typically appear as the drug leaves the infant's system following birth. The window of 48-72 hours is characteristic for symptoms like irritability, feeding difficulties, and other signs of withdrawal, making this timeframe crucial for clinicians to monitor for signs of NOWS in newborns.

Other timeframes, such as 24-48 hours or 72-96 hours, may not align as well with the typical progression of symptoms observed in infants exposed to heroin, thereby establishing the 48-72 hour range as the most accurate representation of the onset for NOWS in cases involving heroin use.