The long-term effects of neonatal abstinence syndrome (NAS) are not well known, but some research suggests it can continue to affect a child into adolescence.

NAS refers to a group of conditions an infant may experience when exposed to certain drugs, particularly opioids, in the womb. NAS occurs when the infant experiences drug withdrawal symptoms.

Around 60–80% of infants exposed to opioids in the womb show signs of NAS.

Although the long-term effects are not fully understood, they may include issues with a person’s vision, hearing, memory, and motor skills.

Read on to learn more about the effects of NAS.

A person holding an infant.Share on Pinterest
d3sign/Getty Images

NAS — sometimes known as neonatal opioid withdrawal syndrome (NOWS) — is a group of physical and behavioral symptoms that can occur in newborns after experiencing exposure to certain substances while in the womb.

These may include stimulants, barbiturates, and benzodiazepines. The most common substance linked to NAS is opiates, a type of pain relief medication.

Once born, the infant’s exposure to the substance suddenly stops, resulting in withdrawal symptoms.

While the cause of NAS is exposure to substances, not all infants born to people using substances during pregnancy will develop NAS. Research from 2018 suggests that the use of more than one substance during pregnancy, as well as genetic factors, can increase the risk.

The exact mechanisms behind the long-term effects of NAS are not fully understood. However, research shows that people with NAS may be more likely to experience some of the following:

  • visual disturbances
  • difficulty hearing
  • impaired motor function
  • short-term memory issues
  • delays in speech development
  • issues with executive functioning

Researchers believe some of these long-term effects may be due to brain development and changes in how neural pathways connect in the brain.

NAS can affect a person from a young age into adolescence. It can influence performance during school and social development.

A 2017 Australian study found that children with NAS performed less well in high school tests than those without NAS.

Additionally, a 2018 study found that infants with NAS were significantly more likely to meet the criteria for educational disability. The study listed some of the most common difficulties being issues with speech development and impairments.

Signs of NAS usually occur within several days of birth. They can last from 1 week to 6 months following delivery.

The symptoms of NAS can vary depending on the type and amount of substance involved. Withdrawal from a substance can cause issues across the body, including in the central nervous system (CNS), autonomic nervous system, and gastrointestinal (GI) system.

CNS symptoms can include:

  • tremors, twitching, or seizures
  • tight muscle tone
  • excessive fussiness or crying
  • difficulty sleeping

Autonomic symptoms can include:

GI symptoms can include:

Along with withdrawal symptoms, an infant with NAS may be at a higher risk of complications, including:

These conditions may require doctors to treat them in the newborn intensive care unit after birth.

If a person is pregnant and uses any drugs that can cause NAS, they should talk with a doctor as soon as possible. They can discuss seeking assistance to stop using these drugs.

A person may want to ask the doctor about medication-assisted treatment if they are unable to stop taking opioids without issues.

NAS is a group of symptoms that can affect an infant exposed to certain drugs in the womb. Infants can experience withdrawal from these substances after birth.

Research suggests that the long-term effects of being born with NAS may affect a person throughout infancy and childhood and into adolescence.

If a person is pregnant or planning to conceive and takes a drug that can cause NAS, they should talk with a doctor.