What causes a baby to have normal size body and really small head before birth?

Microcephaly is a condition in which a baby's head is significantly smaller than normal. It can occur before birth (congenital microcephaly) or develop after birth (acquired microcephaly).

Congenital microcephaly is usually caused by genetic factors, such as mutations in certain genes that are involved in brain development. It can also be caused by infections during pregnancy, such as Zika virus, rubella, cytomegalovirus, and toxoplasmosis. Other factors that can increase the risk of congenital microcephaly include alcohol use, drug use, and malnutrition during pregnancy.

Acquired microcephaly can be caused by a variety of factors, including head trauma, stroke, meningitis, encephalitis, and certain genetic disorders. It can also occur as a result of certain medications, radiation therapy, or exposure to toxins.

Microcephaly can lead to a number of problems, including intellectual disability, developmental delays, seizures, and vision problems. The severity of the problems depends on the degree of microcephaly and the underlying cause.

There is no cure for microcephaly, but there are a number of treatments that can help to improve the quality of life for children with the condition. These treatments include early intervention services, special education, and assistive technology.