What is microcephaly?
Microcephaly is a condition where a baby’s head is smaller than expected, when compared with babies of the same age and sex. It often causes abnormal brain development; however, children with a mild version of the condition might have normal intelligence.
A baby is either born with a smaller head, or the condition can develop as the child grows.
Children with microcephaly often have smaller brains, or brains that have either not developed properly during pregnancy or have stopped growing after birth.
Microcephaly can be an isolated condition, or it might coincide with another birth defect or other condition present at birth.
Microcephaly can range from a mild to a severe condition. Children born with microcephaly might experience a range of symptoms, depending on the severity of the condition, which we will discuss below.
How common is microcephaly?
Microcephaly is a rare condition and affects about 2-12 in 10,000 babies in the U.S.
A child is more at risk of microcephaly if a parent or sibling is affected by the condition or carries the faulty gene.
A child’s risk might also be increased if the mother experiences certain complications during pregnancy.
Types of microcephaly
There are two types of microcephaly:
- Congenital microcephaly is caused by a genetic problem. It is a birth defect, present at birth, which can be passed down through families
- Acquired microcephaly is brought on by an environmental factor that has altered the growth and development of the baby’s brain. This can occur during pregnancy or birth, or could occur later in childhood – for example, as a result of various brain injuries.
What causes microcephaly?
In many cases, the cause of microcephaly remains unknown, but there are a number of different genetic and environmental factors which are known causes of microcephaly:
- Genetic or chromosomal disorders. Microcephaly is what’s known as an autosomal recessive gene disorder. This means that boys and girls are equally affected, and that a child needs to have 2 copies of the gene – one from each parent – to develop the condition. If you are known to have a genetic or chromosomal abnormality, discuss your family’s health history with your healthcare provider as soon as possible. Your doctor will most likely advise genetic counseling
- Infections. Toxoplasmosis, rubella (German measles), cytomegalovirus, or chicken pox in pregnancy can be the cause of microcephaly
- Alcohol or drug use in pregnancy. This increases the chances of microcephaly
- Exposure to toxic chemicals. Methylmercury poisoning is a common example of this cause. It occurs when people eat fish from waters contaminated with methylmercury, or if they eat animals that have eaten grain treated with the chemical. It affects the central nervous system and unborn babies are very sensitive to its effects
- Severe malnutrition in pregnancy. Malnutrition (meaning a significant lack of nutrients from food) can be a cause of microcephaly. Malnutrition at critical periods of development can cause irreversible effects. Therefore it’s important for healthcare providers to focus on nutrition in pregnancy
- Craniosynostosis. This is a condition where the sutures or plates of the baby’s skull fuse too early in life, which means normal growth of the baby’s brain cannot continue. Surgery to separate the bones might be necessary to allow the brain’s growth to continue
- Interruption to blood supply in the brain. Complications that occur in the pregnancy or birth and result in a lack of blood flow and oxygen to the brain can stop the brain from growing
- Traumatic brain injury. Injury to the brain can bring about changes in the ability to regulate emotions, and changes in cognition, including attention difficulties, learning disabilities, and low self esteem. Injury to the brain can also interrupt blood flow to the brain and disrupt brain development
- Zika virus. It has now been confirmed that becoming infected with Zika virus during pregnancy is a cause of microcephaly.
What are the signs and symptoms of microcephaly?
Symptoms of microcephaly are varied, and might be different in each child, depending on the severity of the condition and the age of the child. Signs and symptoms can include any of the following:
- Your baby’s head is much smaller than expected, compared with babies of the same age and sex. During a physical exam, at about 24 hours after birth, your child’s healthcare provider will take your baby’s head circumference measurement. This measurement will be plotted on a special growth chart, based on your child’s gestation at birth. The measurement value for microcephaly is usually two standard deviations below the average, or can be determined if your child’s head circumference is below the 3rd percentile
- Infants with severe microcephaly might have a sloping forehead
- There is failure to thrive
- High pitched cry
- Feeding problems, including difficulty in swallowing
- Muscle spasms or seizures
- Shaky or uncontrolled movement.
How is microcephaly diagnosed?
Microcephaly can be diagnosed during pregnancy by your healthcare provider, during a prenatal ultrasound; however, unless there is severe microcephaly, the condition might not be detectable until the third trimester.
Prenatal ultrasounds are usually used to see internal organs and bones as they function during the pregnancy. Ultrasounds are not always accurate for diagnosis of microcephaly.
During the ultrasound, measurements will be taken of your baby’s head and plotted on a chart. If you have multiple scans throughout your pregnancy, measurements will be compared with each other to ensure growth continues as the pregnancy progresses.
If microcephaly hasn’t been diagnosed prenatally, it’s usually diagnosed from the measurement of the head circumference in the initial postnatal period.
If microcephaly is suspected, your child’s healthcare providers can request additional tests, such as an MRI or a CT scan. These tests can provide critical information on the brain’s structure and development, and can even determine whether, during pregnancy, a baby has had an infection that has affected brain development.
Your child’s primary healthcare provider is also likely to order specific blood tests and a urine test to check for infection and genetic markers.
Why is microcephaly a concern?
Microcephaly is a condition with no cure or standard treatment. It’s a lifelong condition that can cause significant developmental delays, intellectual disability, and various other health conditions.
Each individual can be affected differently, depending on the severity of microcephaly.
In mild cases, children born with microcephaly might not have any other problems. Some severe cases, however, can be life threatening.
The following health problems are linked to children with microcephaly:
- Developmental delays
- Delay in milestones, such as sitting, standing, walking, and speech
- Intellectual disability
- Neurological disorders
- Movement and coordination problems
- Feeding difficulties
- Visual or hearing impairment
- Cerebral palsy
- Facial deformities
- Congenital Zika Syndrome.
A baby who has been diagnosed with microcephaly will require regular follow-up from the medical team. The child’s health will be monitored closely to assess growth and development.
Although the condition is often present at birth, the full extent and the effects of the condition are sometimes not apparent until later. It’s important, therefore, for children to attend regular appointments with their healthcare team, to monitor their development and milestones.
What is the life expectancy of someone with microcephaly?
The life expectancy for a child with microcephaly will most likely be reduced, and the outlook will depend on other medical conditions the child might have.
Seizures are often associated with microcephaly. This problem, in itself, can reduce life expectancy.
Children are unlikely to attain normal brain function, despite treatment or therapy, as their brains are unlikely to develop properly.
What is the treatment for microcephaly?
Due to the nature and range of symptoms caused by the condition, there is no standard treatment for microcephaly.
Treatment will depend on the severity of the condition and your child’s abilities.
Babies with mild cases might not have problems, other than a smaller than expected head, and might have normal intelligence.
Babies with more severe microcephaly cases will most likely require early intervention from their healthcare team to maximize their physical and intellectual abilities.
Treatment focuses on physical and occupational rehabilitation, often in the areas of speech and language therapy, occupational and physical therapy, and neurology support.
Children with microcephaly might also require medication to control certain medical problems, such as seizures, they might experience.
How can I prevent microcephaly?
During pregnancy you can reduce the chances of your baby developing acquired microcephaly by eating well, taking prenatal vitamins, and avoiding exposure to certain toxins and chemicals.
- Avoid alcohol, street drugs, or prescription medications during pregnancy, if possible
- Avoid exposure to toxic chemicals or, if this is not possible, wear personal protective equipment (PPE), such as gloves or a mask, to reduce your exposure
- Avoid raw or under cooked meats
- Wash all fruits and vegetables well before cooking or eating
- Avoid or limit high mercury containing fish, such as shark, marlin, swordfish, and tuna
- Avoid cleaning out the kitty litter tray
- Protect yourself from infections and sexually transmitted diseases (STDs)
- Avoid travel to Zika-affected areas
- Remember the rules of basic hand hygiene
- Attend regular dental appointments and prenatal check ups.
What do if you have concerns
If you feel your baby may be at increased risk of microcephaly or you have concerns regarding a future pregnancy, discuss your pregnancy and health history with your family doctor pre-conceptually if possible, or if not as early as possible. You will likely be referred to genetic counseling for further follow up and support.