Acrania is a highly unusual and fatal fetal abnormality where the upper portion of the skull fails to form. It can be diagnosed during a routine ultrasound evaluation, and is often accompanied with a number of other birth defects. This may result in a miscarriage or stillbirth, because the fetus cannot develop normally, although in some cases the pregnancy may continue to term without intervention. Parents facing a fetal diagnosis of acrania have several options for managing the pregnancy which they can discuss with their care providers.
In fetuses with this condition, the facial bones develop normally, as does the spinal column, but the upper portion of the skull never appears. This can be the result of problems with the migration of cells occurring early in fetal development. It is also associated with amniotic bands, tough fibrous tissue that can interfere with fetal development by wrapping the fetus and constricting it as it grows. Acrania is not preventable, and does not occur because of anything the mother did or did not do during the pregnancy.
A variety of other abnormalities can be seen with acrania. Many fetuses with this condition also have ancephaly, where part of the brain is missing along with the skull and scalp. Cleft lip, heart defects, and gastrointestinal abnormalities can also occur. Acrania on its own is invariably fatal, and these other defects may not be diagnosed unless parents specifically request an autopsy.
Very few cases of this condition have been documented. If ultrasound makes a diagnosis of acrania likely, the doctor may request some additional testing to confirm. Doctors want to be absolutely certain that this birth defect is present before offering a firm diagnosis. After diagnosis, parents have several options. The doctor may recommend termination, as the pregnancy is not viable. Allowing the pregnancy to continue could expose the mother to risk of infection and other complications that might make it difficult to get pregnant again in the future.
Mothers can also opt to carry the pregnancy to term under careful medical supervision and deliver normally. Some families may prefer this, for a variety of reasons, and support is available to mothers carrying fetuses with birth defects that are ultimately fatal. It may be helpful to work with a hospital that is familiar with handling such cases and can provide appropriate care during labor and delivery. This can include working with religious officiants, family, and friends to create a labor and delivery plan that suits the needs of the parents.