IVF 7 Week Ultrasound

[user1472246543]

Heya

When we had the 7 week scan, even though the embryo was implanted 5 weeks earlier, I was 7 weeks 2 days pregnant.
I know they calculate for the equivelent of LMP, but my question is more a technical one.
How does the sonograph detect this? why does it not display the measurement as a 5 week embryo pregnancy? Always wondered this and cannot get an answer - didn't think to ask the sonographers at the time.

When they work it out from LMP, its calculated that you ovulate/conceive around 2 weeks after your last LMP.
So for IVF they add 2 weeks onto the implantation day.
All very normal and nothing to be concerned about.
Congratulations!

@MissLC

When they work it out from LMP, its calculated that you ovulate/conceive around 2 weeks after your last LMP. So for IVF they add 2 weeks onto the implantation day. All very normal and nothing to be concerned about. Congratulations!

Thanks for your reply.

I understand they add 2 weeks on - but how is this done with the sonograph? Is it pre-progammed to add this? How does it know to do this? Wouldn't it just detect an embryo and not display the additional 2 weeks?

So the crown to rump length is usually how they work out how far along it is so the 2 weeks will already be calculated into what they know a baby should measure for the different weeks I think

Yes the measurements just correspond to the expected growth for a certain gestation, that gestation assuming conception at 2 weeks.