QuestionQUESTION: Hi Dr,
I'm confused about conception timing. I went in for an ultrasound at 7 weeks and they gave me an EDD of 2/2/2012. How accurate are those early ultrasounds? Because G.A from the ultrasound would put my LMP to be on 4/28 but if i recall i had my period a week before that around 4/20. So is it wrong? There are two possible fathers one being on 4/26 and my ex on 5/7 so who do you think it could possibly be? I heard sperm can live for 5-7 days? Thanks for your help.
ANSWER: An early ultrasound is accurate within 7 days. With a due date of 2/2/12, your conception date was 5/13 +/- 7 days (5/6-5/20). Most sperm live only 2 days, although a few will live for 5 days. The man from 4/26 could not be the father, since even if his sperm lived for 5 days, they were dead before 5/6.
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QUESTION: Thank you for your response! If my conception date was on 5/13 wouldnt the sperm from 5/7 have died by then also? And so if i had my period on 4/20 does that mean the ultrasound was wrong when it said my period was on 4/28, would conception date be wrong also or did i just ovulate late?
AnswerIf your conception date was 5/6 to 5/20, that is compatible with sex on 5/7. Ultrasound dates are not exact, but close approximations (within 7 days). The actual date of your last period isn't really important, only the day you ovulated and conceived.
