If your dr isn't concerned I wouldn't be. And if she is a little small there is nothing wrong with that, the bigger the baby doesn't mean its healthier. My sisters healthy full term baby was 5lbs, tiny like her mom. My belly was pretty small with all my kids (I carry towards the back more) and my babies were 6.14, 7.2, 7.4

Weight estimates are just that. Also, your belly could look small because babe could be sitting more towards your back. Im measuring about 1-2wks ahead but I’m taking it with a grain of salt because she sits different every day. It makes my belly look smaller and big depending on the day

Every one told me I was small with my now 3m old daughter ......at my 39w appt they tokd me she looked 3 weeks behind and was like 4lbs well...she came out a day before my due date at 7lbs 1oz ...so an average baby....ultrasounds can be wrong