Neonatal abstinence syndrome (NAS) is a group of withdrawal symptoms that newborns experience after being exposed to certain drugs, most commonly opioids, during pregnancy. Because these substances cross freely from the mother’s bloodstream into the baby’s through the placenta, the baby’s nervous system adapts to the drug’s presence. After birth, when that supply suddenly stops, the baby goes through withdrawal. In the United States, rates vary dramatically by region, from about 3 per 1,000 births in Hawaii to 68 per 1,000 births in West Virginia as of 2020.
How Substances Reach the Baby
Drugs that affect the central nervous system tend to dissolve easily in fat and are small enough to pass through the placenta with little resistance. Once they cross over, the drug levels in the baby’s blood quickly match the mother’s. This means a baby whose mother uses opioids regularly is essentially exposed to the same substance throughout pregnancy, and the baby’s developing brain adjusts its chemistry accordingly.
When the umbilical cord is cut at birth, that exposure ends abruptly. The baby’s nervous system, which had been functioning with the drug present, is now suddenly without it. The result is a state of overexcitation across multiple body systems: the brain, the gut, and the body’s temperature and stress controls all react at once.
What Withdrawal Looks Like in a Newborn
Symptoms typically appear within the first 24 to 72 hours after birth, though the timing depends on which substance the baby was exposed to. Longer-acting opioids can delay onset by several days. The signs fall into three broad categories.
The most visible symptoms involve the nervous system. Babies with NAS often have a distinctive high-pitched cry, tremors, increased muscle tone, and difficulty sleeping. They may startle easily, yawn frequently, and sneeze more than expected. In severe cases, seizures can occur.
Digestive problems are also common. Many of these babies feed poorly, have trouble coordinating their sucking reflex, vomit, or develop diarrhea. This can lead to dehydration and poor weight gain if not managed carefully.
The third group of symptoms involves the body’s automatic functions: sweating, fever, unstable temperature, nasal stuffiness, and blotchy skin. Taken together, these signs paint a picture of a newborn whose entire system is in overdrive.
How Withdrawal Is Scored and Monitored
Hospitals use standardized tools to track how severe a baby’s withdrawal is. For decades, the most widely used was the Finnegan Neonatal Abstinence Scoring System, which rates 21 specific signs (tremors, crying, feeding ability, sleep patterns, and others) on a numerical scale. Nurses assess the baby every few hours and tally the score. Medication is generally started when three consecutive scores exceed 8, or two consecutive scores exceed 12.
More recently, many hospitals have shifted to a simpler approach called Eat, Sleep, Console. Instead of scoring dozens of individual symptoms, clinicians ask three functional questions: Can the baby eat well? Can the baby sleep for at least one hour undisturbed? Can the baby be comforted within 10 minutes? If the answer to all three is yes, the baby is considered well-managed without medication. This approach focuses on how the baby is actually functioning rather than cataloging every symptom.
Non-Drug Care Comes First
The first line of treatment for NAS is not medication. Most guidelines now strongly emphasize keeping the baby with the parent in a calm, low-stimulation environment. This means dimming lights, reducing noise, swaddling the baby snugly, and encouraging as much skin-to-skin contact as possible. Breastfeeding is supported when it’s safe to do so, both for nutrition and for the calming effect of closeness.
A key piece of this approach is “rooming-in,” where the baby stays in the mother’s room rather than being transferred to a neonatal intensive care unit. The evidence strongly favors this setup. A meta-analysis published in JAMA Pediatrics found that rooming-in reduced the need for medication by 63% compared to NICU care and shortened hospital stays by an average of about 10 days. Babies who roomed in with their mothers were also more likely to be breastfed and to go home with their families. Separating mother and baby in the NICU, by contrast, can interfere with bonding and increase feelings of guilt and stigma for the parent.
When Medication Is Needed
Some babies, particularly those with severe withdrawal, don’t improve enough with comfort measures alone. When a baby can’t eat, sleep, or be consoled despite consistent non-drug care, medication becomes necessary. The goal is to prevent dangerous complications like seizures, stop diarrhea and vomiting that could lead to dehydration, and bring the baby to a state where feeding and growth can happen normally.
The two primary medications are liquid oral morphine and liquid oral methadone. Both are opioids themselves, given in carefully controlled doses to ease the baby off withdrawal gradually rather than all at once. The dose starts low and is increased only if the baby continues to struggle. Once symptoms stabilize, the medication is slowly tapered until it can be stopped entirely. For babies who don’t respond well enough to a single medication, additional drugs that calm the nervous system can be added.
The length of treatment varies widely. Some babies need medication for just a few days, while others require weeks of gradual weaning. Hospital stays for babies treated with medication are significantly longer than for those managed with comfort care alone.
Long-Term Developmental Effects
One of the biggest concerns parents and caregivers have is whether NAS causes lasting harm. A systematic review and meta-analysis examining 16 studies found that children born to opioid-dependent mothers scored lower than their peers across several developmental measures. Cognitive scores in infancy were notably lower, and the gap persisted into childhood, with lower general IQ and language scores. Parents also reported higher rates of attention problems, behavioral issues directed outward (like aggression), and emotional difficulties directed inward (like anxiety).
These differences are real but described as “modest to high risk,” meaning not every child will be affected, and the severity varies. It’s also difficult to separate the effects of the drug exposure itself from the many other factors that often accompany it, including unstable home environments, poverty, and inconsistent access to healthcare. Children who receive early developmental support, stable caregiving, and consistent follow-up tend to do better. The research makes clear that what happens after birth matters enormously, not just what happened before it.
What Recovery Looks Like
For most babies with NAS, the acute withdrawal phase resolves within the first few weeks of life. Babies managed with comfort care alone may be ready to go home within a week. Those requiring medication typically stay longer, sometimes three to four weeks or more, depending on how quickly they can be weaned.
After discharge, ongoing monitoring is important. Pediatricians typically schedule more frequent check-ups during the first year to track feeding, growth, and developmental milestones. Some babies continue to show subtle signs of irritability, feeding difficulties, or sleep disruption for several months, even after the acute withdrawal has passed. Early intervention programs that support motor skills, language development, and behavioral regulation can make a meaningful difference for children who show signs of delay.