Baby vacum asisted and ct showed diastatic fracture at the posterior frontanel. i read on google that such fractures can grow and i am anxious. ct showed no brain injury and now baby is 4 months very active , and meeting milestones. should i worry?

Fractures only "grow" if a part of the brain covering dura is caught in the fracture line. Google wouldn't consider that in a random search. Worrying about your babies doesn't stop for your lifetime, but I would leave this issue behind and let her doc decide when and if to monitor it in the future. I usually did a random skull x-ray after a few months to monitor healing.