2nd (or 3rd/4th) time moms...

Now tht I've been thinking about it, my last ultrasound was at 28 weeks but he was measuring around 32 weeks. He was almost 4 pounds, I'm wondering for all you ladies who have given birth before, have you had a baby measure bigger during pregnancy & he came AROUND his due date? Should I be expecting him early? My dates shouldn't be off, I had a scan at just 4 weeks, so I know roughly how far I am. So what I'm asking is has anyone had a baby measure big during pregnancy & did he come earlier than expected (not in the case of an emergency) ... or near his date?