You may have seen the unsettling pictures on television: babies with very small heads born to mothers infected with the Zika virus. How does this condition--called microcephaly--affect those infants? And is there any way to avoid causing microcephaly in your unborn child? Here are a few key facts about this uncommon condition. What is microcephaly? With microcephaly, a baby’s skull and brain stop growing either while in the womb or during the first couple of years after birth. This condition is rare; the Centers for Disease Control and Prevention estimates between 2 and 12 babies per 10,000 in the United States are born with microcephaly. A baby with microcephaly may be born with a nearly complete skull or with a very small skull. The smaller the baby’s head is, the more limitations the child will experience. Depending on severity, microcephaly can cause: Seizures Cognitive impairments Developmental delays Impaired motor function Poor coordination and balance Dwarfism Babies with mild cases of microcephaly may experience virtually no adverse effects. These children may exhibit normal intelligence and development, with little impairment. Does anything cause microcephaly besides the Zika virus? While the outbreak of Zika in the U.S. and around the world is bringing attention to microcephaly, the condition can arise for a variety of reasons--or for no known reason, as is usually the case. The most common known causes of microcephaly include the exposure of pregnant women to: Infections, such as rubella (German measles), toxoplasmosis (a parasite often found in cat feces), chicken pox, or the Zika virus Malnutrition Heavy metals like lead and arsenic Traumatic injury to the brain before birth and during infancy Certain chemicals, possibly including those in cigarettes Alcohol It’s worth noting, too, some cases of microcephaly occur due to genetic abnormalities in the child. Down syndrome, for example, can cause head deformities. Can my doctor test my baby for microcephaly before it’s born? Unlike some conditions, such as those caused by chromosomal abnormalities, there is no way to test the blood or amniotic fluid for microcephaly specifically. Sometimes, the condition can be seen during a late-pregnancy ultrasound examination. If you are at high risk for microcephaly due to an infection while pregnant or from exposure to the Zika virus, your doctor will advise you about what steps to take to assess your baby’s head development before and after birth. How can my baby be treated for microcephaly? Unfortunately, there is no treatment for microcephaly. When a baby is born with the condition, its head will not “fill out” as the baby grows. It is not possible, medically or surgically, to enlarge a baby’s cranium to “fix” the problem. That said, your baby can receive treatments for any syndromes caused by microcephaly. For instance, babies with seizures will be treated for that condition. Infants with developmental delays can receive therapy to help them grow to their fullest potential. Can I prevent microcephaly? You may not be able to reduce your risk of microcephaly to zero because the condition can occur for no known reason in otherwise healthy mothers. However, you can take steps to minimize your risk by: Getting prenatal care, including all recommended immunizations, as soon as you know you’re pregnant Taking precautions against the Zika virus if you are of childbearing age Eating a healthy diet and taking prenatal vitamins Avoiding cat feces, including litter boxes Using a condom if your sexual partner has been exposed to the Zika virus, since it can be transmitted through bodily fluids Microcephaly can negatively affect a baby’s intelligence and development. And because most cases of the condition have no known cause, you cannot fully shield your unborn child from it. However, if you take good care of yourself before and during pregnancy, you can feel confident you did everything possible to reduce your baby’s risk of being born with this condition.