What Is Microcephaly?


Mosquitoes in the United States—specifically in the Miami area—are carrying and transmitting the Zika virus. The presence of Zika in mosquitoes in this country is a serious concern to pregnant women.

Previous cases of Zika in the United States occurred in people who had traveled to Central or South America or the Caribbean, or who caught the virus through sex with someone who infected with Zika.

In most people, a Zika infection is barely noticeable. Four out of five people infected with the virus have no symptoms or such mild symptoms that they shrug it off. More severe cases involve a sore throat, red eyes, a rash, and joint aches for several days; unpleasant, but still a passing illness.

However, becoming infected with Zika virus while you are pregnant can cause a serious birth defect known as microcephaly.

A baby with microcephaly has a head that is much smaller than normal. The baby’s brain does not develop or grow properly, which results in a smaller head. In less severe cases of microcephaly, the head is simply smaller. In more severe cases, the baby has a very short forehead and a head that is flattened above the eyebrows.

Microcephaly can sometimes be diagnosed before birth when the baby’s skull is seen to be smaller than expected on an ultrasound exam. After birth, it is diagnosed by comparing the baby’s head circumference measurement to growth charts of head measurements of healthy children, similar to the way a pediatrician determines if the baby is growing normally by comparing to normal measurements. A pediatrician will also ask for x-ray and CAT scans of the baby’s head before making a definite diagnosis. Usually, measurements of the head are not made for at least a day after birth because a baby’s head is sometimes misshapen during birth.

A baby with microcephaly may have developmental delays; impaired cognitive abilities; problems with muscle control, coordination, and speech; and may have seizures. Because the severity of microcephaly can vary, so does the severity of these problems. Some children born with smaller than normal heads have normal development and brain function.

Zika is not the only caused of microcephaly. It can also be caused by rubella (German measles), chicken pox, toxoplasmosis, and cytomegalovirus infections, or by being exposed to certain toxic chemicals during pregnancy. Microcephaly can also be genetic. Another cause is a condition where the bones of the skull fuse too early, which prevents the brain from growing normally. In this case, surgery to open the skull can help.

There is no cure for microcephaly. However, a baby born with microcephaly will do better and have better abilities if he or she receives developmental, speech, and physical therapy early in life.

Valerie DeBenedette
Valerie DeBenedette is an experienced health and medical writer who lives about an hour north of New York City with a dog that is smaller than her cat. Her work has appeared in magazines, newspapers, newsletters, and on websites. She is a member of the National Association of Science Writers.

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