What Happens to Babies Addicted to Drugs?

Babies born to mothers who used opioids or other drugs during pregnancy often go through a period of withdrawal after birth, experiencing symptoms that range from tremors and excessive crying to feeding difficulties and sleep disruption. The medical term for this is neonatal abstinence syndrome, or NAS, and it affects the baby because the drug supply from the mother’s bloodstream abruptly stops at delivery. How severe the withdrawal is, how long it lasts, and what the child’s life looks like years later depend on the substance involved, how it is managed in the hospital, and what kind of caregiving environment follows.

What Withdrawal Looks Like in a Newborn

When a pregnant person regularly uses opioids, the drug crosses the placenta and reaches the developing baby. The baby’s nervous system adapts to the constant presence of the substance. At birth, that supply is cut off, and the baby’s body has to adjust on its own. Symptoms can appear anywhere from a few hours to several days after delivery, and in some cases up to a month later. The most common signs include tremors, irritability, high-pitched or persistent crying, poor feeding, vomiting, sweating, and disturbed sleep. Some babies have muscle stiffness or an exaggerated startle reflex; others have loose stools or sneezing fits. The severity varies enormously from one infant to the next.

Withdrawal isn’t limited to opioids. Babies exposed to benzodiazepines, certain antidepressants, or other prescription medications can also experience what researchers describe as neonatal adaptation issues, which may include feeding disorders, tremors, and changes in muscle tone. In some cases, symptoms stem not from withdrawal but from the lingering effects of the drug itself accumulating in the baby’s tissues, producing toxicity-related signs that tend to show up within hours of birth rather than building over days.¹

How Hospitals Decide When to Step In

For decades, hospitals relied on the Finnegan Neonatal Abstinence Scoring Tool to rate the severity of a baby’s withdrawal. Nurses would score individual symptoms on a numerical scale at regular intervals, and once the score crossed a threshold, pharmacological treatment would begin. This system worked, but it was complex and could lead to a lot of babies being started on medication who might have recovered with supportive care alone.

A newer approach called Eat, Sleep, Console has been gaining ground. Instead of tallying up individual symptoms, it asks three straightforward questions: Can the baby eat adequately? Can the baby sleep for at least an hour undisturbed? Can the baby be consoled within about ten minutes? If the answer to all three is yes, the infant stays with the mother and receives comfort care rather than drugs. A large trial published in the New England Journal of Medicine found that this function-based method has been increasingly adopted and is shifting how hospitals manage withdrawal.²

Rooming-In Instead of the NICU

One of the most significant changes in how hospitals care for these babies has been the shift away from automatically admitting them to the neonatal intensive care unit. The older approach separated newborns from their mothers, placed them in bright, noisy environments, and relied heavily on medication. Rooming-in flips that model: the baby stays with the mother in a quiet, low-stimulation room and receives skin-to-skin contact, breastfeeding support, and soothing from a parent rather than a rotation of medical staff.

The results have been striking. At one hospital that adopted rooming-in as the standard of care, only about 3.5% of infants who roomed-in over a five-year period needed medication, compared with more than 83% of opioid-dependent infants who had been admitted directly to the NICU. The median hospital stay for rooming-in babies was five days versus 24 days for those in the NICU.³ The mechanisms behind this are exactly what you’d expect: bonding, breastfeeding, and consistent parental soothing help regulate the baby’s nervous system and reduce the severity of withdrawal symptoms.⁴

Rooming-in programs typically bundle several interventions together. Along with keeping the baby in the mother’s room, they emphasize swaddling, skin-to-skin contact, and breastfeeding support, since greater parental involvement in soothing is thought to be the primary reason the approach works.⁵

When Medication Is Necessary

Some babies have withdrawal symptoms severe enough that comfort care alone isn’t sufficient. When an infant can’t eat, can’t sleep, or is inconsolable despite best efforts, hospitals turn to pharmacological treatment. The standard approach for opioid withdrawal is to give the baby a carefully dosed opioid replacement, most commonly morphine or methadone, and then gradually taper the dose over days to weeks as the baby stabilizes.⁶

Morphine has historically been the most widely used option, but methadone may shorten the treatment course. One randomized trial found that the median length of opioid treatment was about 14 days for methadone compared with 21 days for morphine.⁷ If a baby’s symptoms remain uncontrolled even at the maximum opioid dose, an add-on medication like phenobarbital or clonidine may be introduced.⁸ Buprenorphine is also emerging as a treatment option for the baby, with early results looking promising.

How the Mother’s Treatment Affects the Baby’s Risk

For pregnant women with opioid use disorder, abruptly stopping opioids is dangerous for both the mother and the fetus. The standard of care is medication-assisted treatment, typically with either methadone or buprenorphine. Both are far safer than continued illicit drug use, but they are not equivalent when it comes to the baby’s withdrawal risk.

Babies exposed to buprenorphine before delivery develop NAS at a lower rate than those exposed to methadone. A large study published in the New England Journal of Medicine found that about 52% of infants exposed to buprenorphine in the 30 days before delivery experienced NAS, compared with roughly 69% of those exposed to methadone.⁹ Another study using different methods confirmed the direction of this effect, finding that methadone-exposed infants were about 1.3 times more likely to develop NAS, even after accounting for the fact that women on methadone tended to have more severe addiction.¹⁰

This doesn’t mean methadone is the wrong choice. Some women do better on methadone clinically, and the most important thing is that the mother stays in treatment. An untreated opioid use disorder carries far greater risks to the pregnancy than either medication does.

What Happens When Babies Are Also Exposed to Nicotine

Most research focuses on opioids in isolation, but in reality, many women who use opioids also smoke or use other substances. Nicotine is one of the most common co-exposures, and it appears to make things worse for the baby. A scoping review found that combined opioid and nicotine exposure during pregnancy was associated with lower birth weight, shorter birth length, and more severe NAS symptoms compared to opioid exposure alone.¹¹ Methamphetamine co-exposure similarly complicates the picture, altering newborn neurobehavior in ways that can make diagnosing and treating opioid withdrawal harder.¹²

Long-Term Cognitive and Motor Development

The withdrawal period itself resolves within weeks. The bigger question for many parents and caregivers is what prenatal drug exposure means for the child’s development over years. The research here is concerning but not without nuance.

A meta-analysis of studies on children with prenatal opioid exposure found measurably lower cognitive scores in early childhood, with a moderate effect size at ages zero to two and a somewhat smaller but still significant gap at ages three to six. By school age and into adolescence, the difference was no longer statistically significant in the pooled data, though the authors noted high variability across studies. Motor development also showed lower scores in exposed children.¹³

A Norwegian longitudinal study tracking individual children told a somewhat more worrying story. Children in the exposed group scored lower on cognitive tests at every assessment from age one through age eight and a half, and the gap actually widened over time rather than closing. At age one, the difference was about 6.5 points; by eight and a half, it had grown to about 18 points. Interestingly, the widening gap was driven mainly by the girls in the exposed group, whose scores declined relative to controls as they got older. Boys in the exposed group scored consistently lower from the start, without the same pattern of widening.¹⁴

Behavioral and Mental Health Challenges

Cognitive effects are only part of the picture. Children with prenatal opioid exposure also show higher rates of behavioral difficulties, and these tend to worsen as the children grow older. A study using both parent and teacher reports found that exposed children had significantly more problems in several behavioral domains by age eight and a half, with attention difficulties standing out as a particular concern.¹⁵ Growth curve modeling in another study confirmed that emotional and behavioral difficulties worsened over time relative to same-age peers, not just compared with a baseline.¹⁶

By adolescence and young adulthood, the stakes get higher. A prospective study following prenatally exposed youth who had been raised in permanent foster or adoptive homes found that they were more than three times as likely to experience major depressive episodes, alcohol abuse, or ADHD compared with non-exposed peers.¹⁷ That these outcomes persisted even in stable adoptive homes suggests a biological component, though environment clearly also matters.

Vision Problems That Often Go Unnoticed

One outcome that rarely makes it into public discussions is vision impairment. Children born to mothers on methadone maintenance during pregnancy have an unusually high rate of eye problems. In one study, children exposed to methadone in utero were more than twice as likely to fail a vision assessment compared with unexposed children, and about 20% of the exposed group had nystagmus, an involuntary rhythmic eye movement, with no other explanatory diagnosis.¹⁸

A larger study following over 300 children with prenatal substance exposure found that about 15% had strabismus (crossed eyes) at their initial assessment, compared with under 3% in the control group. By age five, more than 42% of the exposed children had no demonstrable binocular vision, and about 28% had significantly reduced visual acuity in one or both eyes.¹⁹ These are the kinds of problems that, if caught early, can be treated or managed, but they require screening that not every child receives.

How Much Is Biology and How Much Is Environment

One of the hardest questions in this field is separating what the drug itself does to the developing brain from what happens afterward in the child’s environment. Babies born to mothers with substance use disorders often face poverty, instability, exposure to environmental toxins like lead, and in some cases neglect or abuse. All of those independently affect development.

A study that followed cocaine-exposed children into young adulthood offered a useful window into this question. Young adults with prenatal cocaine exposure had lower IQ scores regardless of whether they were raised by birth families or placed in foster or adoptive care, suggesting a biological effect. But those placed in non-kinship foster or adoptive homes had better vocabulary skills, lower lead exposure, more stimulating home environments, and higher high school graduation rates than those who stayed in birth or kinship care. The rates of problematic substance use and incarceration, however, did not differ between the two groups.²⁰ The takeaway is that some cognitive deficits appear to be baked in by prenatal exposure, but many functional outcomes are modifiable through the quality of the caregiving environment.

At the molecular level, researchers are investigating whether prenatal drug exposure leaves lasting marks on the baby’s DNA through epigenetic changes, particularly alterations in DNA methylation patterns that can affect how genes are expressed without changing the genetic code itself. This is still early-stage science, but it offers one plausible mechanism by which a temporary chemical exposure during pregnancy could produce long-lasting developmental effects.²¹

The Cost of Hospital Care

Neonatal withdrawal is expensive. A study of pediatric hospitals across the United States found that babies with NAS stayed an average of nearly 19 days, compared with about 3 days for other newborns, and their average hospital costs were roughly ten times higher, at about $37,600 per admission versus $3,500.²² A separate national analysis estimated total hospitalization costs for NAS at about $573 million in 2016 alone, with the average cost per infant around $22,500. Most of those costs fell on Medicaid, which covered the majority of NAS births.²³ The shift toward rooming-in and the Eat, Sleep, Console approach has the potential to significantly reduce these costs by shortening hospital stays and reducing the need for medication.

Why Punishing Mothers Makes Things Worse

Several U.S. states have enacted laws that criminalize drug use during pregnancy or classify it as child abuse. These policies are intended to protect babies, but the evidence suggests they do the opposite. A systematic review of punitive state policies found that criminalization, civil child abuse statutes, and related measures were consistently associated with decreased use of prenatal care. When pregnant women fear arrest, losing custody, or being placed on a child abuse registry, they avoid the healthcare system.²⁴

A study examining birth data from states that adopted explicit prenatal drug criminalization found that these laws were associated with thousands fewer births per 100,000 receiving any prenatal care, along with fewer facility-based deliveries.²⁵ Less prenatal care means withdrawal goes unplanned for, delivery complications increase, and the baby’s transition is harder than it needs to be. The medical consensus has largely moved toward treating substance use during pregnancy as a health condition requiring support, not a crime requiring punishment.

Changes in the Baby’s Gut Bacteria

An area of active research that rarely comes up in popular discussions involves the gut microbiome. Animal studies have shown that prenatal methadone exposure significantly alters the composition of gut bacteria in both mother and offspring. Specifically, beneficial bacteria like Lactobacillus and Bifidobacterium were depleted, while other bacterial groups expanded.²⁶ These shifts in the mother’s microbiome appear to be transmitted to the offspring, with strong correlations between the bacterial communities of opioid-treated mothers and their babies.²⁷ Given the growing understanding that gut bacteria influence everything from immune development to pain sensitivity, these changes could contribute to some of the gastrointestinal symptoms seen in NAS and potentially to longer-term health effects, though that connection is still speculative in humans.