They wouldn't be a month out honey but bare in mind a pregnancy actually lasts 38 weeks from dtd, it's 40 weeks from your last period.
For example if you a tiny sac can be seen in the uterus, but the baby and its heart beat may not be detected yet.
However, the accuracy of the ultrasound examination is always dependent on the skill of the sonographer and the quality of the equipment.
Usually the expected date of delivery (EDD or EDC) is calculated from your last menstrual period - if the early dating scan calculates the EDD to be within 5 days of the EDD from your last menstrual period.
does anyone know how accurate the dating scans are - is there a possibility of them being a 1hole month out?
had scans at 6w5d and 12 w5d and 20w4d - all match up to the same date but i remeber another date the month before when we did the deed but my partner did not complete in me - is there any chance the scans cud be 4 weeks out?