Anencephaly is a serious congenital condition where a baby is born without parts of the brain and skull. This occurs during early pregnancy when the neural tube, which forms the brain and spinal cord, does not close completely. Babies with anencephaly typically have a small brain and may only have a brainstem, which controls basic functions like breathing. Most infants with anencephaly do not survive long after birth, often living only a few hours or days. The condition is usually detected through prenatal imaging, such as ultrasound, and is associated with a lack of folic acid during pregnancy, which is important for proper neural tube development.