conception confusion

[lucy2813]

Hello,
I have been browsing the questions and been very impressed by those that seem to have their head completely around lmp, conception and due date info. I get confused very easily so please help!

My question is regarding the conception date.

Background is this.... Sex on July 29th and sex again Aug 15th. Am absolutely unsure of my LMP but it might have been Aug 2nd [not info I want to use as a definite as I am unsure].

Because of uncertainty the doc sent me for early us on sept 20th where fetus was measured at 6w and 5d.

Edd keeps varying between May 6th to May 10th.

I want the second date of sex to be the one but doubt my dates. Can anyone shed some light and also tell me why they believe one date over another.

Thankyou!

[AnnieBrooke]

The only way this would differ is if you had said specifically to the sonographer at the time, "Regardless of how far I am along medically speaking, can you tell me what would have been my likely conception date?"  But if you were not that specific, she would have spoken the medical language in dating pregnancy.  All the charts are calibrated to that kind of counting.

[AnnieBrooke]

Yes, all medical counts (and medical books and charts and graphs) are calibrated to starting the pregnancy count at the first day of the last period, or as you say, 'adding a 2-week gap on top of gestational age.'  There would be a very significant differentc between an ultrasound reflecting 6w5d and one reflecting 8 or 9 weeks.

[lucy2813]

Thanks for your comments. I had a follow up question about the early U/S though.

There would be a significant difference between an ultrasound done at 6w 5 days as opposed to one that reflected between 8- 9 weeks?

Also, do sonograph technicians measure pregnancy the same way everyone does? As in adding the 2 week gap ontop of gestational age?  (I hope that made sense).

Thank you.

[AnnieBrooke]

I get conception at around August 18, based on the ultrasound on September 20th saying 6w5d (which would be, approximately, 4w5d from conception).  It sounds much more likely to me that the second candidate is the father.  (Sperm can easily live three days in your body, but certainly not twenty days.)  Do a DNA test for sure, but I'd go in pretty certain of the result, since it's pretty hard to fool a 6w5d ultrasound, especially by as much as 20 days.  Later due dates can vary because babies grow at different rates, but that early, they're pretty consistent.

[lora24]

I believe she is right if ur us says ur 6w 5d the u ovulated mid aug and concieved keep in mind when the dr gives a due date they usually caunt from the first day of ur last period not conception

[Clysta]

Based on your due dates, I'm getting that conception happened in August--from the 9th, up till the 21st. Sometime in that general area. I would it more towards it being the second date, but in reality only a paternity test can tell for sure.