Question for you ladies :)

First, a little background: PCOS, uncomplicated pregnancy so far, almost 35 weeks, but have been having growth ultrasounds (twice in the past month) because fundal height is always low, baby measures fine or so i thought.

The last 2 u/s (one at 30 weeks and one at 33) have shown that his head circumfrance is in the 75th %-tile and then the 80th %-tile. All other measurements measure right at 50th%-tile. So my OB says she's sending my records to a peri and if they think it's significant they will call me. She reassures me it could be normal, strictly precautionary and they may not even call me. So, I'm like fine... Not a big deal.

next day I get a call and they've set me up an appointment "as soon as they could". I go in next Wednesday to have an u/s with the peri. Anybody have any experience with this? My google searches have led me no where and from what I'm seeing it isn't a big deal at all. The only metion of a larger head circumference is with autism, but even then its more related to a growth spurt in and around 3 months of infancy. I kinda feel like I'm doing all this all for them to say, "yup, big head... Lucky you..." I mean, is this something that might change the game plan or my OB being overly cautious.

any insight would be appreciated and of course, I will be asking both my OB and peri at my appointment next week.