Abnormal brain development frequently accompanies microcephaly. The condition can often occur alongside other major birth defects. Microcephaly can, however, be the only abnormality present.
The condition affects between 2 and 12 babies per 10,000 live births each year in the United States.
- Microcephaly is a rare condition.
- It can be present at or after birth.
- The risk of microcephaly is increased by exposure to infections during pregnancy, such as rubella.
- Microcephaly is often accompanied by other medical conditions, such as seizures, developmental delays, and balance problems.
- The severity of microcephaly varies from person to person.
Microcephaly is a shrinking of the brain and skull caused by a range of genetic conditions, infections, and diseases.
The cause of microcephaly cannot always be determined. However, there are certain conditions that might be related to its development.
Conditions that pose a risk for developing microcephaly include:
- genetic or chromosomal abnormalities, such as Down syndrome
- infections during pregnancy, such as rubella, toxoplasmosis, cytomegalovirus, chickenpox, and possibly the Zika virus
- severe malnutrition
- craniosynostosis, or premature fusing of the skull suture line
- cerebral anoxia, a condition involving decreased oxygen delivery to the brain of a fetus
- maternal uncontrolled phenylketonuria (PKU), a birth defect that restricts the body's ability to break down a specific amino acid
Environmental factors can also increase the risk of microcephaly. If, while in the womb, a fetus is exposed to drugs, alcohol, or toxins, the risk of the infant developing a brain abnormality is higher.
CT scans can help identify microcephaly.
Occasionally, the presence of microcephaly can be seen on a second-trimester or third-trimester ultrasound and diagnosed before the infant is born.
For a child to be diagnosed with microcephaly after birth, the child will undergo an in-depth examination process.
The diagnostic process for microcephaly can include:
- a physical exam, including head circumference evaluation
- family history and evaluating the head sizes of the parents
- charting head growth over time
Once microcephaly is diagnosed, doctors could also use CT and MRI scans or blood tests to evaluate the severity and cause of the microcephaly and any other associated conditions.
Some of these tests might also provide the healthcare team with information about the presence of an infection in utero that may have caused structural brain changes.
There is currently no treatment or cure for microcephaly.
Treatment focuses instead on interventions to manage the condition and relieve linked health problems, such as seizures. If an ongoing process is contributing to the microcephaly, such as malnutrition, this will be addressed as well.
Infants with mild microcephaly typically only require routine check-ups. However, those with a more severe form of the condition may require early childhood intervention programs to strengthen and maximize physical and intellectual capabilities.
These programs will often include speech, physical, and occupational therapies.
A condition called craniosynostosis can cause microcephaly. In cases of craniosynostosis, the joints between the bones of an infant skull fuse together prematurely, preventing the brain from growing properly. However, this condition is typically reversible with surgery to help reshape the skull.
Speak with your healthcare provider about the personal risks of having a child with microcephaly and the steps you can to lower that risk. In any pregnancy, it is important to reduce the risk of complications by avoiding alcohol, drugs, and other toxins.
Chickenpox, rubella, cytomegalovirus, and toxoplasmosis are linked to the condition, so taking preventative measures against these diseases is also recommended.
Possible connection between microcephaly and Zika virus
Zika has been linked to microcephaly.
Due to the recent concern over the risk of microcephaly and Zika virus, the Centers for Disease Control (CDC) recommend that women who are pregnant avoid traveling to regions in which the disease has a presence.
Click here for a full, up-to-date rundown of countries cited by the CDC as presenting a risk of Zika.
Dr. Mark DeFrancesco, President of the American College of Obstetricians and Gynecologists (ACOG), advised the following in a statement supporting the travel guidelines set in place by the CDC.
"Travel to regions with ongoing Zika virus outbreaks is not recommended for women who are pregnant or women who are considering pregnancy."
Information on Zika is developing and changing fairly rapidly. Follow this link for the most recent statements and recommendations from ACOG.
To learn more about the CDC's travel recommendations, please visit their travel health notices web page.