Ultrasound.

so which one is more accurate? @thehowtohippie

Your first is probably off your period. The second is based on how big the baby measured during the ultrasouns

Due date by My last period and due date set by ultrasound were a week apart for me. Had her on my original due date which was set by my period

One may be based on your last menstrual cycle and one on the dating ultrasound. It's just an estimate so pick one. Only 2-5% of moms give birth on their due date anyway ;)

my Dr came up with two different due dates one was by my last period and the other was what baby was measuring they were 2 weeks apart as well I didn't make it to either of them cause he set my EDD as the one from.my last period

your right..@thehowtohippie, but I would still like to know how they come up with different dates

They're only 2 days apart it doesn't really matter