Question about u/s timing for heartbeat & how doctors calc due date?

[cjp]

When they do the u/s for heartbeat, how do they determine when? 6 weeks from what date?? I did a 5 day transfer on March 30th. Also, does anyone know how the doctor's figure out due dates when it's done through IVF? Let me know if you need more dates for anything! Thanks

[BC-MAV]

I think I posted this same question on the surrogacy BB. The RE had an EDD according to the retrieval then he changed the EDD according to the day of the 3 day transfer. Let me see if I can find the post on the surrogacy BB.

[BC-Sweedie]

All Dr's are different, but h/b can be seen after 6 weeks, but not always that early. For me, it was 7+ weeks with my last pg.

I don't know the IVF/dd thing, but I'd think it would be calculated by LMP..???

[BC-MAV]

I think 6 weeks is the earliest they can detect a heartbeat on a good u/s machine. I had mine detected at that point... very small, but beating at 78.

Here is the link to the post on the surrogacy BB about trying to calculate due dates!!!

http://www3.fertilethoughts.com/foru...hreadid=304167

[marya]

To do the dating you need to figure out what your ovulation day/first day of last period should have been if you had had a natural 28 day cycle (since that's where the whole 40 weeks comes from).

For you ovulation day should be March 25 (5 days prior to your 5 day transfer). That makes your first day of last period March 11. Even if that wasn't the date, use March 11 to figure out how far along you are and when you are due.

So if you are having a u/s at 6 weeks pg, then April 22 would be your 6 week marker. That is really the earliest you can see a h/b though. 7 weeks is generally when they do a "real" heart beat check, so that would be April 29. At 6 weeks they are generally checking for how many sacs and whether there is a fetal pole. A h/b is just bonus.

[BC-MAV]

I don't think LMP is very accurate when doing IVF.... your cycle is so manipulated by the BCP's and Lupron.... I think it's better to us the transfer day as the conception point. Your RE or Dr. should be able to give you an EDD... I mean these things are EXACT when you are doing IVF. No questions about when eggs were retrieve or when things fertilized or when those little embryos were transfered. This MIRACLE I had no idea when the last AF was or if I ovulated. The u/s showed I ovulated from the right side, but who knows when it was? The RE is just going by my guestimates of when AF last was and the u/s showing how many weeks gestation the embryo is.

[marya]

Mav, no LMP isn't accurate, but OBs will want to use it all the time. That's why I gave the formula for figuring out the "fake" LMP. You need to ignore your real LMP and memorize the date of the "formula" one. It is *much* easier to just give everyone (obs/lab techs, etc.) the date two weeks before your retrieval, or two weeks + the age of your embie before your transfer than to try to explain to them that this was an IVF/FET/DE cycle and LMP isn't really accurate and you know the age of your embie, yadda, yadda, yadda. By using transfer and or retrieval date you can come up with the LMP that matches exactly where you really are in your pgcy.

Sorry for the confusion in my post.