When Is Macrocephaly Diagnosed?

Macrocephaly is customarily diagnosed if head circumference is greater than two standard deviations (SDs) above the mean. Relative macrocephaly occurs if the measure is less than two SDs above the mean, but is disproportionately above that when ethnicity and stature are considered.

How is macrocephaly diagnosed?

Macrocephaly can be normal or caused by genetic disorders or other disorders. Diagnosis is made before birth through routine ultrasound tests or after birth by measuring the head circumference. Doctors usually do imaging tests to look for brain abnormalities and sometimes blood tests to look for a cause.

At what age is microcephaly diagnosed?

Early diagnosis of microcephaly can sometimes be made by fetal ultrasound. Ultrasounds have the best diagnosis possibility if they are made at the end of the second trimester, around 28 weeks, or in the third trimester of pregnancy. Often diagnosis is made at birth or at a later stage.