how accurate are dating scans?

[jophie]

ok im 33 weeks pregnant due 29th feb (leap year) according to the dating scan. by my dates and my lmp im due feb 8th. im 33 weeks gone yet i messure 37 weeks. had a scan this week baby is not big got the right amount of fluid ect.. just wondered if anyone eles went into labor by there dates and not the dating scan dates????

[Luci]

they are very accurate... usually to the exact dayx

[Helen08]

the dating scans are almost always accurate cause the measure the babys lengh an weight an stuff

[quest4info]

When I was pregnant with my daughter my dates worked out my due date to be 29th July. Yet my scan said I was due 21st July. Daughter arrived 1st August, 10 days late. But was she really 10 days late???