So according to my lmp I should be due Nov. 24 they then changed my due date twice to 12/8 then 12/13 so I've been tracking by the 12/13 date but now baby is measuring almost 2 1/2 weeks ahead every time like today I'm 21w 3days and baby measures 23w 6days is it normal to be that far off, I guess my main concern is because I have a cerclage that they are supposed to remove at 36 weeks but with that much of a difference they could be waiting until 38 weeks which from my reading can be dangerous.