I had a scan at 31+6 and estimated weight was 4lbs 4oz which I was told was just above average, as the general rule is that they gain 1lb a fortnight, with 8 weeks to go I'd be looking at 8lbs 4oz at term. However, my friend was told 6lb 10oz at 36 weeks and her baby was born at 39 weeks weighing in at 6lb 5oz!