Microcephaly – Symptoms and Causes
Overview
Microcephaly is a rare condition where a child’s head is smaller than expected for their age and sex. This often happens because the brain does not grow properly, either before or soon after birth.
Several things can cause this condition, including genetic issues or problems in the environment during pregnancy. Children with microcephaly may face challenges with development and learning.
Signs and Symptoms
The main sign of microcephaly is a head that is much smaller than normal.
| Symptom | Description |
|---|---|
| Small head size | Markedly smaller head than peers |
| Sloped forehead | Forehead has a noticeable downward angle |
Doctors measure the distance around the top of the head (head circumference) and compare it to standard growth charts.
- Head size falls below what is expected for age and sex
- Some children may simply have small heads, but microcephaly means the size is far below average
- In severe cases, a child’s forehead may appear sloped
These signs help healthcare providers notice microcephaly early.
When to see a doctor
If a baby’s head seems smaller than expected or does not appear to be growing, parents or caregivers should contact a healthcare provider. Early checks can help spot any health problems.
Causes
Microcephaly can happen for many reasons. Often, it is due to problems when the brain is forming, either before birth or shortly after.
A main cause involves genetic factors. Some children inherit gene changes from their parents. These changes can slow down brain growth and affect the shape of the head.
Early closing of skull bones (known as craniosynostosis) is also linked to microcephaly. When bones in the baby’s skull join too soon, the brain does not have enough room to grow. Doctors often use surgery to fix this.
The following list shows other possible factors:
- Low oxygen to the baby’s brain before or during birth
- Serious infections during pregnancy, such as Zika virus, rubella, and chickenpox
- Substance exposure, like drugs, alcohol, or chemicals, before birth
- Poor nutrition for the mother while pregnant
- Unmanaged health conditions, such as phenylketonuria (PKU) in the mother
| Cause | How It Affects Brain Growth |
|---|---|
| Genetic changes | Limits normal brain development |
| Craniosynostosis | Restricts skull and brain expansion |
| Infections | Damages fetal brain cells |
| Low oxygen | Prevents needed blood and oxygen delivery |
| Exposure to toxins | Harms brain forming in the womb |
| Malnutrition | Starves brain of nutrients |
| Maternal PKU | Increases risk of abnormal brain growth |
All these factors may lead to a smaller head size, as the brain does not grow as expected.
Possible Issues
Children with this condition can face a mix of challenges. Common problems include:
- Speech and movement delays
- Trouble with balance and coordination
- Shorter height
- Changes in how the face looks
- High levels of activity
- Learning problems
- Seizures
Prevention
Taking steps before and during pregnancy can help lower the chance of having a child with microcephaly. Parents should work closely with healthcare providers to figure out possible causes. Knowing if genetics play a part is important.
If genetics are involved, meeting with a genetics counselor can explain potential risks for future pregnancies.
Vaccinations protect against illnesses that may increase the risk of microcephaly in developing babies. For example, vaccines against rubella and Zika virus can reduce certain risks.
Pregnant women should avoid contact with anyone who might have infections that can harm a growing baby.
There are other helpful actions, such as:
- Managing Medical Conditions: Keeping illnesses like diabetes under good control before and during pregnancy.
- Avoiding Certain Substances: Not using alcohol, tobacco, or illegal drugs when pregnant.
- Eating a Balanced Diet: Getting enough nutrients and necessary vitamins.
Healthcare providers may review medications to be sure they are safe during pregnancy.
