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A member asked:
My scan date says 7 weeks 3 days does that mean conception occurred 5 weeks 3 days ago if your lmp was not known do they measure the sac?
A doctor has provided 1 answer
Exactly!: You are correct. The extra 2 weeks are added because of an old convention, and we date the pregnancy by "menstrual weeks". Full term = 40 weeks from lmp. We always use your menstrual age (even if we don't know your lmp) and we never really talk about fetal age (time since conception). I wish we could change this convention, it's confusing! by the way, there is a 4-7 day margin of error w that date.
Answered 4/26/2014
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Related Questions
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If lmp and 3 separate scans all give a edd of 4th October what are the possible dates of conception?
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When does it mean when a doctor considers the LMP due date and conception if the ultrasound is in a 7-10 day agreement with the lmp? Need an example
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Aug 7th Scan says 12 w 4 d. no lmp to go off. whats accuracy in telling me proper age of baby? and is that from conception?
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How accurate is an early ultrasound? On 6/15/18 baby measured 5w6d. Between what dates could conception of happened? LMP 5/5.
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1st ultrasound says crl 8mm 6w5d. 2nd says crl 28mm, 9w4d. 3rd , crl 60.9mm 12w4d.Are these supposed to date back to lmp? When was conception?
A doctor has provided 1 answer
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