Fetal neurosonography

What is fetal neurosonography?

A targeted, detailed examination of the fetus's central nervous system (brain and spinal cord). The examination can be performed from the end of the first trimester - but most often from the early second trimester due to an emerging abnormality. It often requires follow-up, because some diagnoses can only be made later in pregnancy, until then the abnormality can only be described as a suspicion. Different diagnoses can be made at different stages of pregnancy. This is due to the continuous changes in the brain during pregnancy.

How is the examination performed?

During neurosonography (abdominal and vaginal ultrasound), a detailed examination of the brain and spine is performed for possible abnormalities. In order to describe the exact spatial extent of the lesion, the brain must be examined in detail in all three dimensions. In addition to describing the abnormality, its possible causes must also be sought (e.g. genetic abnormality, infection, suspected bleeding), because this is the only way to determine the expected problems.
During the examination, the structure of the brain, the cerebral cortex, brainstem, and pituitary areas, the appearance of certain cranial nerves, the cerebral fluid system (cerebroventricular ventricles and the cerebral cistern system), the vascular system supplying the brain, and the structure of the spine are checked. Furthermore, it must be reviewed whether the current state of the brain corresponds to the given gestational age, because deviations from this may indicate an abnormality even in otherwise normal appearances.
Due to the above, neurosonography can only be performed by a specialist who is experienced in the subject, who is particularly interested in it, and who is familiar with fetal brain development, and who also has adequate knowledge in the area of ​​the causes behind the changes (e.g. genetic abnormalities).

In what cases is fetal neurosonography recommended?

• Central nervous system abnormalities detected during a screening ultrasound examination, or suspicion thereof
• Brain or spinal abnormality occurring in a previous pregnancy
• Hereditary brain or spinal abnormality in the family history
• Fetal heart development abnormality during pregnancy
• Twin pregnancy (in case of shared placenta)
• In case of suspected or confirmed intrauterine infection
• Use of drugs or medication that may damage the development of the central nervous system
• A deviation described in a genetic test that may be associated with a disorder of the central nervous system, or in case of a genetic finding of "uncertain significance"