how accurate are first trimester ultrasounds?

[monica931]

How accurate is CRL measurement ( crown rump length ) in dating pregnancy at 9 weeks 4 days ?

[AnnieBrooke]

Unless you also had sex with someone else on April 24, 25, 26, 28, 29 or 30, it sounds like the sex with the boyfriend on the 27th was what got you pregnant.

[Misslady259]

so crown to rump would only be GA age?

[monica931]

i was with my boyfriend 2 days after that US date, i got the US monday june 17th and i had sex with boyfriend april 27th

[AnnieBrooke]

Then count back 7 weeks 4 days for a conception date.  It might be one or possibly two days off, but not more.  How close are your choices to each other, and to that date?

[monica931]

thank you Annie, yes they told me i was 9w4d GA

[AnnieBrooke]

Pretty accurate.  Maybe a day or two off.  But are you thinking that when they tell you 9 weeks 4 days, it's 9 weeks 4 days from conception?  Because they are counting from the first day of your last period.  You'd be about 7 weeks 4 days from conception.