Fetal Alcohol Syndrome: Causes, Signs & What to Do

Fetal alcohol syndrome is a serious and preventable condition that can develop when alcohol is consumed during pregnancy. It is the most severe form of fetal alcohol spectrum disorder (FASD) and affects thousands of children and families across Canada each year. Alcohol passes through the placenta and directly impacts the developing baby’s brain and body, causing effects that can range from mild to severe and may last a lifetime.

What Is Fetal Alcohol Syndrome and How Does It Affect Babies?

Understanding the risks of alcohol during pregnancy is one of the most important steps expectant parents can take. In Canada, fetal alcohol spectrum disorder is recognized as a leading preventable cause of developmental disability. Knowing the signs, seeking early diagnosis, and accessing the right support can make a meaningful difference for affected children and their families.

What Is Fetal Alcohol Syndrome?

Types of Fetal Alcohol Spectrum Disorders (FASDs): Characteristics and Management

Type	Key Characteristics	Common Challenges	Management Approach
Fetal Alcohol Syndrome (FAS)	Distinct facial features (thin upper lip, smooth philtrum, small eye openings), growth deficiency, confirmed prenatal alcohol exposure	Intellectual disability, learning difficulties, behavioural problems, poor impulse control	Early intervention programs, special education support, behavioural therapy, regular developmental monitoring
Partial FAS (pFAS)	Some but not all facial features of FAS, growth problems may be present, confirmed or unknown alcohol exposure	Memory and attention deficits, social difficulties, adaptive functioning challenges	Individualized education plans (IEPs), occupational therapy, social skills training
Alcohol-Related Neurodevelopmental Disorder (ARND)	No distinct physical features, significant brain-based impairments, confirmed prenatal alcohol exposure	Poor executive function, math difficulties, judgment problems, mental health disorders	Cognitive-behavioural therapy, structured routines, academic accommodations, mental health support
Alcohol-Related Birth Defects (ARBD)	Structural or functional defects of organs (heart, kidneys, bones, hearing), confirmed prenatal alcohol exposure	Heart defects, hearing or vision loss, skeletal abnormalities, kidney problems	Specialist medical care (cardiology, audiology), surgical interventions as needed, regular health screenings
Neurobehavioural Disorder Associated with Prenatal Alcohol Exposure (ND-PAE)	Confirmed prenatal alcohol exposure, significant neurobehavioural impairment across three domains	Severe mood dysregulation, attention deficits, adaptive behaviour difficulties	Multidisciplinary team support, psychiatric assessment, family-centred care, community support services

Fetal alcohol syndrome (FAS) is the most severe form of a group of conditions known as fetal alcohol spectrum disorder (FASD). It develops when alcohol consumed during pregnancy reaches the baby through the placenta. The baby’s body cannot process alcohol the way an adult’s can, so it builds up in the blood and affects normal development.

The brain and nervous system are especially vulnerable. Alcohol can disrupt how brain cells form and connect, leading to lifelong challenges with learning, behaviour, and physical development. In Canada, FASD is one of the leading known causes of preventable developmental disability.

For more information, visit Health Canada’s official health resources for guidance on alcohol use during pregnancy.

How Does Alcohol Affect a Developing Baby?

When a pregnant person drinks, alcohol enters the bloodstream and crosses the placenta. This is the organ that delivers nutrients and oxygen to the baby. Because the baby’s liver is not fully developed, it cannot break down alcohol effectively.

As a result, alcohol stays in the baby’s system much longer than in the mother’s. This prolonged exposure can harm developing organs, particularly the brain. Even a small amount of alcohol at the wrong time during development can cause lasting damage.

Which Factors Increase the Risk?

Several factors influence how severely alcohol affects a developing baby. These include:

• How much alcohol is consumed — larger amounts cause more harm
• When during pregnancy alcohol is used — the first trimester is especially critical for brain development
• How often drinking occurs — binge drinking (five or more drinks at one time) is particularly harmful
• Other substances used — smoking, recreational drugs, and certain medications increase the risk
• The mother’s overall health — chronic health conditions can make the effects worse
• Genetic factors — some babies may be more sensitive to alcohol’s effects than others, even with the same exposure

Furthermore, there is no known safe amount of alcohol during pregnancy. Medical experts in Canada and around the world recommend avoiding alcohol completely throughout all three trimesters.

Signs and Symptoms of Fetal Alcohol Syndrome

The signs of fetal alcohol syndrome can affect a child’s appearance, growth, brain function, and behaviour. Symptoms vary depending on how much alcohol the baby was exposed to in the womb.

Facial Features

Children with FAS often have distinct facial features. These include a smaller-than-average head size, small eyes, a flattened area between the nose and upper lip, a thin upper lip, and a small or upturned nose. These features can be difficult to notice in very young infants. However, they typically become more visible between ages two and three.

Interestingly, some of these features may become less obvious in adolescence and adulthood. One feature that often remains is a nose that appears unusually prominent compared to the rest of the face.

Growth and Physical Development

Babies born with fetal alcohol syndrome are often smaller than average. Many are born weighing less than 2,500 grams (about 5.5 pounds). They may also be shorter than other children their age throughout childhood and adolescence.

Growth challenges tend to persist even with good nutrition and medical care. In addition, some children with FAS have structural birth defects affecting the eyes, ears, heart, urinary tract, or bones.

Brain and Nervous System Effects

Alcohol has the strongest impact on the developing brain. Newborns affected by FAS may show low muscle tone and poor coordination right after birth. Some babies also experience tremors and a weak grasp reflex.

As the child grows, problems with hand-eye coordination may also become noticeable. These neurological effects are often permanent, though early support and therapy can make a significant difference in quality of life.

Behavioural and Learning Challenges

Children with fetal alcohol syndrome often struggle with learning and behaviour. Newborns may be irritable, have trouble feeding, or have difficulty bonding with caregivers. These early signs can be mistaken for other conditions, which is why a full medical evaluation is important.

As children reach school age, they may have trouble paying attention, following instructions, and managing their emotions. Problems with memory, reasoning, and impulse control are also common. These challenges can affect school performance, friendships, and daily life well into adulthood.

Conditions That Look Similar to Fetal Alcohol Syndrome

Some other conditions share symptoms with fetal alcohol syndrome. This can make diagnosis more complex. For example, long-term use of certain anti-seizure medications during pregnancy, such as phenytoin (hydantoin), can cause a similar pattern of physical and developmental features in newborns.

Certain genetic conditions may also produce overlapping symptoms. Therefore, a thorough medical assessment is essential to reach the correct diagnosis. A paediatrician or developmental specialist can help distinguish FAS from other conditions with similar presentations.

Is There a Safe Amount of Alcohol During Pregnancy?

This is one of the most common questions asked about alcohol and pregnancy. The honest answer is that no safe level of alcohol during pregnancy has ever been established. Research clearly shows that heavy drinking causes severe harm. However, even lower amounts of alcohol carry risk because every pregnancy and every baby is different.

Canadian medical associations, along with the World Health Organization, strongly recommend complete abstinence from alcohol during pregnancy. This is the safest approach for both the parent and the baby.

If you are pregnant and have been drinking, stopping as soon as possible is still beneficial. It is never too late to reduce exposure and protect your baby’s development.

Diagnosis and Early Intervention

Early diagnosis of fetal alcohol syndrome gives children the best chance for a healthy life. When doctors know that a mother consumed alcohol during pregnancy, they can begin monitoring the baby closely right after birth. The earlier support begins, the better the outcomes for physical and cognitive development.

Diagnosis typically involves a physical examination, developmental assessment, and a review of the mother’s history of alcohol use during pregnancy. Being open and honest with your healthcare provider is extremely important. There is no judgment — only a desire to help your child get the right support as early as possible.

According to Mayo Clinic’s guidance on fetal alcohol syndrome, early intervention programmes that include educational support, behavioural therapy, and family counselling can significantly improve outcomes for affected children.

Support for Parents Who Struggle With Alcohol Use

If you are pregnant and struggling with alcohol dependence, please know that help is available across Canada. Many provincial health plans cover addiction counselling and detoxification services. Seeking help before or early in pregnancy is one of the most important steps you can take for your baby’s health and your own.

Your family doctor can connect you with local addiction support programmes and mental health resources covered under your provincial health plan.

When to See a Doctor

You should speak with a healthcare provider as soon as possible if you are pregnant and drinking alcohol, or if you are planning a pregnancy and want to stop drinking. Your family doctor is the best first point of contact. They can provide non-judgmental guidance, refer you to a specialist, and help create a plan to protect your baby’s health.

If you do not have a family doctor, a walk-in clinic can be a good starting point. Walk-in clinics across Canada can assess your situation, provide referrals, and connect you with addiction or prenatal care services in your area.

If your child shows signs of developmental delay, unusual physical features, or behavioural difficulties, speak with your family doctor or paediatrician promptly. Early diagnosis of fetal alcohol syndrome leads to earlier support — and better outcomes.

Key Takeaways

• Fetal alcohol syndrome is caused by drinking alcohol during pregnancy and can affect a baby’s brain, body, and behaviour for life.
• Alcohol crosses the placenta and reaches the baby directly — there is no safe amount of alcohol during pregnancy.
• Signs of FAS include distinct facial features, low birth weight, poor coordination, and challenges with learning and behaviour.
• Early diagnosis leads to better outcomes. Being honest with your healthcare provider about alcohol use during pregnancy is essential.
• Help is available across Canada through family doctors, walk-in clinics, and programmes covered by provincial health plans.
• If you are struggling with alcohol dependence, seeking support before or early in pregnancy is one of the most protective steps you can take for your baby.

According to Public Health Agency of Canada’s guide to fetal alcohol spectrum disorder, this information is supported by current medical research.

For more information, read our guide on thyroid disorders that can affect pregnancy health in Canada.

This article is for informational purposes only and does not replace professional medical advice. Always speak with your family doctor or a qualified healthcare provider about any concerns related to pregnancy, alcohol use, or your child’s development.