There are many causes for enlarged ventricles within developing babies. At this point the overall size of the babies head is important for determining if you will be able to deliver vaginally or if you will require a c-section. The change in the size of the ventricle may indicate the growth of the baby or further change in the size of the ventricle. After the birth of the baby a formal head U/S will need to be performed, and possibly a CT scan or MRI. Based on your childs appearance and examination at birth furhter testing may need to be performed.