Large abdominal circumference!?

Araeha

I just had my anatomy ultrasound at 21+2 and baby was measuring BIG. My weight gain is right on track and I had a normal BMI prior to pregnancy. My fundal height was a week ahead which is normal.... Baby was 1lb 3oz and his abdominal circumference is in the 93.5 percentile. My midwife recommends that I have an early 1hr glucose test this week and repeat a growth scan with my 2 hr glucose test at 28 weeks... Has anyone had this happen? Did you have GDM?