When a pregnant woman uses alcohol and/or other drugs, these substances pass readily through her bloodstream and across the fetal blood-brain barrier. If a woman uses substances regularly, particularly throughout the third trimester, the unborn baby can develop a physical dependence to these substances. When the child is born, the flow of the drug is abruptly cut off, and the baby’s nervous system can trigger the agonizing symptoms of withdrawal. This condition is known as Neonatal Abstinence Syndrome (NAS).
While opioid misuse is most readily associated with causing NAS, newborns may withdraw from a variety of substances including nicotine, alcohol, amphetamine-type drugs, benzodiazepines, and even certain antidepressants. Neonatal Abstinence Syndrome is also commonly experienced by babies whose mothers are on a prescribed regimen of methadone or buprenorphine throughout pregnancy. Despite this, doctors recommend that pregnant women with opioid use disorders remain on medication-assisted-treatment throughout pregnancy, as experiencing withdrawal symptoms during pregnancy may place the mother and baby at greater risk of harm.
Not all babies exposed to substances will have withdrawal symptoms. Those who do will typically begin showing symptoms within 24 to 72 hours after birth. However, in some cases (particularly with drugs like benzodiazepines), symptoms may not appear for several days. Withdrawal symptoms vary from mild to severe and can last from one week to three months.
For more information about NAS and the effects specific substances can have on a developing fetus, visit: https://www.drugabuse.gov/publications/research-reports/substance-use-in-women/substance-use-while-pregnant-breastfeeding