Alcohol during pregnancy changes a baby’s brain chemistry

Pregnancy shapes the brain more than any other period in life. Each day builds networks for learning, memory, and emotion. But alcohol can disturb that process and leave marks that last a lifetime.

Fetal alcohol spectrum disorders affect about one in twenty school-aged children in the United States.

These conditions cause learning problems, poor self-control, and trouble adjusting to change. Scientists have long searched for the brain circuits behind these issues.

Brain cells affected by alcohol exposure

A new study by Dr. Jun Wang and Dr. Rajesh Miranda from Texas A&M University’s Naresh K. Vashisht College of Medicine has found strong clues.

Their work shows that alcohol exposure before and soon after birth damages brain cells that help with decision-making and flexibility. These changes also raise the risk of compulsive alcohol use later in life.

“It’s exciting,” Wang said. “We’ve identified a specific brain cell in offspring affected by early alcohol exposure that’s directly linked to problems with flexible thinking and impulse control, and this gives us a clear target for better understanding and eventually developing more effective treatments of FASD.”

Alcohol in pregnancy harms the brain

The researchers focused on cholinergic interneurons, or CINs, in the dorsomedial striatum. These cells control how the brain responds to change. Alcohol exposure during pregnancy or around birth cut their number and weakened their activity.

“CINs are like the conductors of the brain’s decision-making orchestra,” Wang explained. “They are largely responsible for the decision-making network in the brain.”

When alcohol disturbed these conductors, the brain lost its rhythm. The neurons fired less often and released less acetylcholine, the chemical that helps people learn and adapt.

The result was slower learning and poor flexibility – the mental skills needed to switch strategies and respond to new challenges.

How behavior changes

The team tested how these brain changes affected behavior. Mice learned to press levers for food rewards. When the researchers reversed which lever gave which reward, control mice adapted quickly.

The alcohol-exposed group could not. They kept pressing the same lever, unable to change their response.

“This highlights how prenatal alcohol exposure can have lasting effects on a brain’s flexibility and adaptability to new environments,” Wang said.

The finding mirrors human struggles seen in FASD, where people often stick to old habits even when situations change. It links cell-level disruptions to real-world learning problems.

Alcohol in pregnancy raises addiction risk

The damage went beyond brain signals. Adult mice exposed to alcohol before birth later showed compulsive drinking behavior.

Even when alcohol was mixed with a bitter compound to make it unpleasant, they kept drinking.

“When key decision-making brain cells are compromised, they don’t just stop at brain chemistry. They manifest in real-world behaviors, like addiction and compulsive behavior,” Wang said.

The study suggests these early brain changes may blunt how the brain processes negative outcomes. A person may continue harmful behavior even when it causes discomfort or risk.

The role of timing

The scientists used two models. One involved mothers that drank voluntarily before and during pregnancy.

The other model exposed mothers to alcohol vapor during specific days of fetal development. Both approaches damaged the same brain circuits but in different ways.

Prenatal exposure interfered with neuron development during key growth stages. Perinatal exposure, which continued after birth, disrupted how those neurons functioned.

Together, these findings show that any exposure – early, late, or throughout – can cause harm.

Lessons for prevention

“Our findings represent a major step forward in FASD research. By uncovering how early alcohol exposure changes brain chemistry, we’re able to move from describing symptoms to transitioning into treating root causes,” Wang said.

The research also supports what doctors have said for decades: no amount of alcohol is safe during pregnancy.

“Even limited alcohol consumption during sensitive developmental windows can have profound and lifelong consequences,” Wang said.

Future therapies may target the damaged cholinergic system. Nutrient supplements like choline, which help make acetylcholine, could support recovery. Earlier studies have shown that choline can improve attention and memory in FASD cases.

Why no alcohol is safe

This study connects brain chemistry, behavior, and lifelong risk in a way that makes prevention urgent. It shows how alcohol disrupts both thinking and self-control by silencing key brain cells.

“This is a preventable disorder,” said Wang. “There is no safe amount, no safe time, to consume alcohol during pregnancy.”

The message is simple but powerful. Protecting a developing brain starts with one choice: complete avoidance of alcohol.

The study is published in the journal Neuropharmacology.

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