Neonatal Abstinence Syndrome (NAS)

What is Neonatal Abstinence Syndrome?

Neonatal Abstinence Syndrome (also called NAS) is a condition that occurs when a baby withdraws from certain drugs they were exposed to during pregnancy. It is most often caused by opioids, including prescription pain relievers like codeine, hydrocodone (Vicodin®), oxycodone (OxyContin®), and tramadol, as well as street drugs like heroin (also an opioid). You may hear NAS also called NOWS. NOWS stands for neonatal opioid withdrawal syndrome. NOWS is the same as NAS except it’s caused only by opioids. NAS can also result from exposure to antidepressants, barbiturates, or benzodiazepines (sleeping pills).

When you take these drugs during pregnancy, they pass through the placenta, which supplies the baby with oxygen and nutrients. This exposure can cause serious health problems for the baby after birth. If you’re pregnant or planning to become pregnant and using these medications, talk to your healthcare provider.

What are signs of NAS?

Signs of NAS can be different for every baby. Most happen within 3 days (72 hours) of birth, but some may happen right after birth or not until a few weeks after birth. These signs can last from 1 week to 6 months after birth.

If you notice any of the following in your baby, contact their healthcare provider immediately:

• Body shakes (tremors), seizures (convulsions), overactive reflexes (twitching) and tight muscle tone
• Excessive crying or a high-pitched cry
• Difficulty feeding or gaining weight
• Breathing problems, including rapid breathing
• Fever, sweating or blotchy skin
• Trouble sleeping and lots of yawning
• Diarrhea or vomiting (throwing up)
• Stuffy nose or sneezing

Signs of NAS depend on:

• The type and amount of drug used during pregnancy
• How long you used the drug and how your own body breaks it down
• Your baby’s gestational age at birth (number of weeks of pregnancy)

What complications can NAS cause for your baby?

Babies with NAS may have health conditions that need treatment in the newborn intensive care unit (also called NICU) after birth. In addition to having withdrawal signs, babies with NAS are at increased risk of:

• Low birthweight. Weighing less than 5 pounds, 8 ounces at birth.
• Jaundice. Yellow skin and eyes. This happens when your baby’s liver isn’t fully developed or working.
• Seizures
• Sudden infant death syndrome (also called SIDS). Unexplained death of a baby under 1 year old, often during sleep.

We need more research to see how NAS affects a child in the first few years of life and longer but possible issues include:

• Developmental delays. Developmental delays are when your child doesn’t reach developmental milestones such as sitting, walking, talking, having social skills and having thinking skills, when expected..
• Motor skill problems. These are problems with your baby’s bones, muscles and movement.
• Learning and behavior problems. 
• Speech and language problems
• Sleep disorders
• Hearing and vision problems

How is your baby tested for NAS?

Healthcare providers may use these methods to diagnose NAS:

• NAS scoring system. This measures how severe your baby’s withdrawal symptoms are and guide treatment.
• Urine and meconium tests to check for drugs. Meconium is your baby’s first bowel movement.
• A review of the parent’s medical history and drug use.

How is NAS treated?

Your baby’s treatment may include:

• Medication to treat or manage severe withdrawal symptoms. Once withdrawal is under control, your baby gets smaller doses of the medicine over time.
• Getting fluids through a needle into a vein (also called intravenous or IV) to prevent your baby from getting dehydrated.
• Being fed higher-calorie baby formula. Some babies with NAS need extra calories to help them grow because they have trouble feeding or slow growth.

During treatment for NAS, your baby may be fussy and hard to soothe. Doing these things can help calm your baby:

• Room in with your baby at the hospital.
• Give your baby skin-to-skin care (also called kangaroo care). 
• Swaddle your baby in a blanket.
• Keep your baby’s room quiet and the lights dim.
• Breastfeed your baby. If possible, try to feed your baby on demand. 
• Give your baby a pacifier. 

Your baby’s healthcare team is the best source and guide to help decide when your baby can go home. A lot depends on whether your baby is feeding and sleeping well, gaining weight, and showing fewer withdrawal signs.

After your baby is home, be sure to go to all follow-up and well-baby checkups, even if your baby is doing well. Your provider will check your baby at these visits for problems that may be linked to NAS.

If your baby has signs of developmental delays, talk to the healthcare provider about early intervention services. Services include therapy to help a child talk, walk, learn self-help skills and interact with others. Getting services as early as possible can help improve your child’s development.

What can you do to help prevent NAS in your baby?

To reduce the risk of NAS:

• Talk to your healthcare provider: Inform them if you use opioids or other medications. Don’t stop taking these drugs without medical advice, as sudden withdrawal can harm your baby.
• Consider medication-assisted treatment (MAT): Medicines used in MAT include methadone or buprenorphine and may reduce the severity of NAS.
• Use birth control if not planning pregnancy: Methods like IUDs, implants, and condoms can help prevent unplanned pregnancies while using medications.
• Avoid substance misuse: You may need to stop taking certain medicines or change to medicine that’s safer for your baby. Use only medications prescribed to you and as directed. Seek help if you’re struggling with substance use.

More information

• Mother to Baby
• Substance Abuse Treatment Facility Locator

See also: Preventing NAS in your baby infographic, Caring for a baby with NAS infographic, Prescription opioids during pregnancy, Prescription medicine during pregnancy

Last reviewed: January 2025