Investigating the cause of death

We understand how important it is to receive answers during such a difficult time. Not understanding what happened can make grieving even more difficult.

We hope that the investigation can help provide some answers about what happened and, when possible, why.

In the following sections, we explain the different stages of the investigation aimed at understanding the circumstances of the death and, when possible, identifying the cause.

Professionals involved

When a child dies unexpectedly, the presence of professionals such as coroners and police officers can be especially distressing for you the parents. In a moment already marked by shock, grief, and confusion, their involvement may feel intrusive or difficult to understand. It is important to know that their role is defined by law in Quebec and is intended above all to seek answers with thoroughness, respect, and impartiality. Their mission is not to accuse or to judge, but to understand the circumstances of the death and to ensure that no element has been overlooked. Their presence does not mean there is suspicion or fault; it is a standard part of the process when a death occurs suddenly or without clear explanation. In the next sections, we will explain in detail the role of these professionals.

Finding the cause of death

Investigating the cause of a child’s death is a complex process that is often not well understood and can be overwhelming for many families. When a death occurs suddenly and with no clear explanation, a team of specialists becomes involved to help determine what happened.

A key part of the investigation is the autopsy, which provides essential information to help determine the cause of death.

In the previous section, we explained the role of each professional involved in the investigation. In the following sections, we will review the findings that resulted from this process and what are the next steps.

It is important to note that at the Jeremy Rill Centre, we follow the recommendations of the highest international authorities to maximize the chances of accurately identifying the cause of death.

If a young baby or a child dies anywhere in the Province of Quebec, the investigation is as complete and extensive as in the best centers in the United States or Europe.

At any time, parents can ask the coroner about the progress of the investigation.
They can also contact the Jeremy Rill Center by phone at 1-514-412-4400, extension 23399, or by email at [email protected]

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Genetics

Genetics is the study of genes. Genes have characteristics that we inherit from our parents and ancestors. That is why we look like our parents: we share genes with them.

Genes are found in all the cells of our body. Their role is to give instructions to make molecules called proteins. Simply put, genes give orders, and proteins carry out those orders so that our body works properly.

Genes are made of DNA. When a couple has children, DNA of the parents is copied and passed on to the child. DNA is made up of small units, like building blocks, arranged in a specific order. Each person has a unique organization of genes, which is why we are all different.

If the order of the units in a gene changes (this is called a mutation), it can affect the protein that is produced. If the protein does not work properly, this can lead to health problems, especially involving the heart, the nervous system, or the immune system.

Mutations in genes often happen by chance. For example, during the COVID-19 pandemic, the virus underwent mutations that led to new variants, which we heard a lot about.

A geneticist is a specialist who studies genes, heredity, and genetic variation in people.  They evaluate and treat patients with genetic disorders, provide genetic counseling to families, explaining risks, testing options, and inheritance patterns. They also order and interpret genetic tests.

When to refer to genetics after a sudden death

There are three situations where it’s important to refer a family to a geneticist after the sudden death of a child:

1. The child’s death might be caused by a genetic disease. Often, the results of the autopsy make us think that a genetic disorder could be the cause. These results can be found in the muscles, brain, liver, or heart. This can also be true in cases of infection if a genetic problem with the immune system is suspected.
2. There is no clear cause of death identified at the autopsy, and we want to complete the investigation with genetic testing.
3. There is a family history of possible genetic problems, or there have been other sudden, unexplained deaths in the family.

What happens during a genetics consultation?

A meeting is organized with members of the genetics team (a genetic counselor and a medical geneticist) to explain the process, answer parents’ questions, and help them decide whether they want to proceed with genetic testing.

The following steps are usually taken:

• A detailed review of the mother’s pregnancy and delivery records, as well as the child’s medical history.
• A complete family tree covering three generations, including the family’s medical history.
• Genetic testing on tissue from the deceased child and from the parents, to look for genetic mutations that could explain the death and help prevent other deaths in the family.

A small amount of tissue is always kept frozen after the autopsy in case additional tests are needed. Part of this tissue may be used for genetic testing.

DNA collected from the parents’ blood or mouth is compared with the DNA of the deceased child to identify possible genetic factors that may have contributed to the child’s death.

In about 5 to 6% of cases (as of 2026), this type of testing identifies either a genetic disease or a genetic predisposition that may have played a role in the child’s death.

The geneticist will inform the parents of the test results and explain what follow-up, if any, is needed.

Cardiology

Heart diseases causing sudden death in young babies and older children are rare. However, when a cause is found, heart diseases are the second leading cause of death. Some heart diseases are genetic, meaning they can run in families, especially those affecting the heart muscle or causing heart rhythm problems (arrhythmias). This is why families often need to follow up with a doctor to monitor heart health.

The cardiologist

A cardiologist is a doctor who specializes in heart diseases. They receive many years of extra training to diagnose and treat heart problems in both children and adults. Cardiologists are not surgeons, but they work closely with heart surgeons who fix heart defects in children if needed.

Some cardiologists specialize in heart rhythm problems (like arrhythmias), while others specialize in heart muscle diseases (like cardiomyopathies).

When to refer to a cardiologist after sudden death

There are three situations where it’s important to refer a family to a cardiologist after the sudden death of a child:

1. If the child’s death might be caused by a genetic heart disease, like a heart muscle problem found during the autopsy.
2. If an electrocardiogram (ECG), a test that measures the electrical activity of the heart, is abnormal in a family member, such as a parent or another child.
3. If there is a family history of heart rhythm problems or heart diseases that could be genetic.

It is usually a doctor from the Jeremy Rill Center who requests the cardiology consultation. Sometimes, the family doctors will also proceed with this consultation as soon as they learn of the death from the parents.

How a cardiology consultation works

The consultation begins with a discussion about the family’s medical history, particularly any heart diseases. The cardiologist will also ask about symptoms, such as heart pain or shortness of breath, especially during exercise.

In addition to a full physical exam, cardiologists use tests like the electrocardiogram (ECG) and the echocardiogram.

The ECG is a quick and simple test that records the electrical activity of the heart using small sensors placed on the chest. Even if this test has been done before, the cardiologist will do it again.

The echocardiogram is a more detailed test that allows the doctor to see the heart and detect problems like congenital defects or heart muscle diseases. This test is similar to the ultrasound used during pregnancy to see the baby.

Before the consultation, the cardiologist usually receives the autopsy report of the deceased child to check for any heart issues. The cardiologist reviews this information before meeting with the family.

At the end of the consultation, the cardiologist will explain whether a heart disease or heart rhythm disorder is a possible cause. They may also recommend further tests, such as genetic tests, and suggest if follow-up care is needed.

Immunology

Immunology is the science that studies the immune system, which is the body’s natural defense against germs such as bacteria and viruses.

When the immune system is working well, the body reacts to infections by showing clear signs, such as fever, fatigue, or pain. These signs help alert parents that their child is sick.

But in children who have a weakened or abnormal immune system, these warning signs might not appear. The child may look healthy, even if they are developing a serious infection.

Why is this important in cases of sudden death?

In cases of sudden and unexpected death in children, infection is one of the most common causes (when a cause is found). This is why it is very important to check if there might be a problem with the child’s immune system, especially if the child appeared healthy before passing away.

These conditions can appear at any age, even in children who had never seemed sick before. They can prevent the body from fighting off infections properly.

What does an immunologist do?

An immunologist is a doctor who specializes in the immune system. When they assess a child or family members, they look for signs of immune system problems. They:

• review the child’s medical history (past illnesses, vaccines received, etc.),
• ask about infections in the family,
• may do a blood test to check the antibodies and how the immune system is working,

If needed, the immunologist may also recommend genetic testing to see if there is an inherited condition affecting the immune system, and whether other family members could also be at risk.

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Having another child

The sudden and unexpected loss of a child is a heartbreak that words can hardly capture. We know how overwhelming the grief, fear, and uncertainty can feel. In the midst of such loss, it is natural to wonder:
“Could this happen again?”

We want to offer you guidance and reassurance, while acknowledging the weight of your feelings. There are two situations to consider:

• The cause for the death has been identified after careful medical investigation.
• No specific cause could be found.

We will also share information about risk factors that can sometimes be reduced or prevented.

Above all, please know this from the bottom of our hearts: the sudden death of another child is extremely rare. Your fears are understandable, and your feelings are valid. You are not alone, and support is available as you navigate these difficult thoughts and decisions.

We are here to listen, to answer your questions, and to walk alongside you with compassion and care.

When the cause of death is known

Infection

Sometimes a severe and rapid infection can explain the death. This happens in a specific and sudden situation.

In this case, the risk for another child is usually very low, unless a similar infection occurs. The doctor may suggest preventive measures or special follow-up.

Inmany cases, the physician at the Jeremy Rill Center refers the family to an immunology or genetics specialist. Tests may be done to check how well the immune system works. The results will be explained to the parents, and the level of risk will be evaluated based on the findings.

Suspected or confirmed genetic disease

Sometimes medical tests suggest a genetic condition, such as:

• certain metabolic diseases
• inherited heart conditions
• disorders associated with seizures

In these cases, a consultation in medical genetics is recommended.

Tests may be performed on parents and siblings. Depending on the condition, the risk may be low, moderate, or high. However, the risk can be measured and medically monitored.

If another child is born, close medical follow-up will be provided.

At the Jeremy Rill Center, families are referred for genetic testing whether a cause has been identified or not.

Other causes

There are also other, less common causes that may sometimes explain a sudden death.

As with the causes mentioned earlier, the physician at the Jeremy Rill Center will explain to the parents whether there is any risk for another child. The doctor will also discuss any tests that may be recommended, if needed.

Unexplained sudden death

In many cases, even after thorough investigations, no clear cause is found.

When tests do not reveal anything, the risk of a similar event happening to another child remains low. It is never zero, but it is rare.

In these situations, we recommend reducing risk factors as much as possible.
A risk factor is not a direct cause, but it increases the likelihood that something may happen.

Several risk factors are known during the first six months of life. After six months, no specific risk factors have been clearly identified.

Most important risk factors in the first 6 months

1. Smoking during pregnancy

The more cigarettes a mother smokes, the higher the risk. However, reducing smoking already lowers the risk if quitting completely is difficult.

2. Sleeping on the stomach

Babies should always be placed on their back to sleep. Once a baby can roll over independently, the risk decreases significantly. However, it is still recommended to place the baby on their back.

Since the recommendation to place babies on their backs to sleep, unexplained deaths have decreased by more than half.

3. Unsafe bed-sharing

• Never sleep with a baby on a couch or other soft furniture. The baby could become trapped and have difficulty breathing.
• Do not bed-share if you are very tired or under the influence of alcohol, drugs, or medications that cause drowsiness. In these situations, you may not wake up in time if the baby is in distress.

In these situations, a safe sleep space must be provided for the baby.

When we talk about a risk being low or high, what do we mean?

In cases of sudden death, the risk is shown as the number of babies who die compared to the total number of births each year. The general risk in Quebec is 2 babies who die for every 10,000 births.
This can change depending on whether certain risk factors are present.

• When the three most important risk factors are removed and the baby is breastfed, the risk can be as low as 1 baby who dies per 100,000 births.
• However, if the three major risk factors or more are present, the risk can be as high as one death in 200 births.

Should a monitor be used for the next child?

Electronic monitors are available to track breathing, heart rate, movement, or oxygen levels in babies.

It is important to distinguish between:

• commercial monitors sold in stores, and
• medical monitors prescribed by a doctor

Only a physician can prescribe a medical monitor after a full evaluation.

Do monitors prevent Sudden Infant Death?

There is no scientific evidence showing that electronic baby monitors prevent sudden infant death. For about 25 years (from the 1980s to the late 1990s), monitor use did not reduce the number of deaths. However, public health campaigns promoting back sleeping reduced these deaths by 50% in just a few years.

Important considerations if using a commercial monitor:

• False alarms: These can be frequent and very stressful for parents.
• False sense of security: Parents may pay less attention to signs of illness or may not avoid known risk factors.

If you absolutely want a monitor, the team at the Jeremy Rill Center can refer you to a specialized medical team.

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