Is an active baby in the womb a good sign of a healthy weigjt gain for bby?

Not necessarily. Activity is not necessarily a sign of healthy weight gain, though it is certainly more reassuring for appropriate development. Your doctor will measure the height of your fundus at each visit, which is an indication of the baby's weight gain. You should have regular activity daily during the third trimester and if you have concerns do not hesitate to contact your provider.