dating scans

[helpless419]

Are dating scans accurate when using them to determine due date when there is no lmp to go off of? I have had irregular periods all my life and sometimes i will only have a cycle 3 or 4 times a year.

[Majikat]

i found out with my first when i was about 4 months pregnant with my first and he was born 3 weeks before the due date weighing 6lb 14oz so i think  that it was pretty accurate you can prob say give or take a week with the later dating u/s but the ones before 12 weeks with be pretty right on within days

[helpless419]

I had my first ultrasound at 9w6d. then i had an ultrasound at 13w 6d aand was measuring 14w4d.

[Aaron_N_SophiasMommy]

Typically yes they are fairly accurate give or take a day or so, if you get and early ultrasound. Ultrasounds done later on could be off depending what rate your baby is growing

[MamaBear0612]

They can be pretty accurate, but it depends a lot on when you get your first ultrasound...the further along you are, the less accurate they are. Ultrasounds in early pregnancy are usually considered pretty accurate (within about a week) because the baby in early stages develops in a very particular pattern. How far along are you?