So every time I have had an ultrasound he has measured 5 days behind, so I'm 21 weeks and 5 days today he's measuring 21 weeks. My due date calculated by my period is Jan 1st. My period was March 27th and I got my first positive test on April 24th, the soonest I could have. I did some calculations on the internet and it says according to my period the day I got a positive is the soonest I could have so I'd assume I'm right on target for the due date, is he just small? I really want him to come in December for sentimental reasons, no I won't force it I know he will come when ready but if there's a chance he'll come late I'd like to be prepared, my doctor keeps saying he isn't changing my due date 5 days isn't enough to change it... Please comment!