Microcephaly is a condition in which a child's head is much smaller than the heads of other children of the same sex and age. Micro means small, and cephaly is related to the Greek word for head. Children with microcephaly also usually have smaller brains or brains that have developed abnormally. Microcephaly is often congenital, but it can develop after birth.
A relatively rare condition, microcephaly occurs in approximately 25,000 U.S. births annually. Genetic issues often cause microcephaly, but environmental issues are sometimes implicated. Children with microcephaly may have a range of associated issues.1‘Microcephaly.’ Mayo Clinic, Mayo Foundation for Medical Education and Research, 25 June 2020, www.mayoclinic.org/diseases-conditions/microcephaly/symptoms-causes/syc-20375051.,2‘Microcephaly: Boston Children’s Hospital. Boston Childrens Hospital, www.childrenshospital.org/conditions-and-treatments/conditions/m/microcephaly.
Prenatal Causes of Microcephaly
Genetic mutations often cause microcephaly, and chromosomal abnormalities, such as Down syndrome, may play a role in the development of microcephaly. An expectant mother's poor diet, use of alcohol and exposure to drugs and certain chemicals may cause microcephaly to develop in her unborn child. If the expectant mother acquires infections, such as rubella, varicella, toxoplasmosis or Zika virus, during pregnancy, the baby may have microcephaly.
Lack of oxygen to the baby's brain during pregnancy or delivery is another potential cause of microcephaly. The condition may also arise if the child's mother has uncontrolled phenylketonuria.1‘Microcephaly.’ Mayo Clinic, Mayo Foundation for Medical Education and Research, 25 June 2020, www.mayoclinic.org/diseases-conditions/microcephaly/symptoms-causes/syc-20375051.