Hi there ~
It is better to follow the condition closely and have regular ultrasound
examinations. Since you are in the sixth month of your pregnancy
it may be a good idea to consult with a neonatologist to have the baby resuscitated immediately after birth. However please be aware that hydrocephalus
is mostly a treatable condition. I think that you need to reassure yourself of that and not become anxious. Consult an obstetrician who is ready to help.
Take care and have a lovely day !