FET natural cycle (non-medicated) - reading different opinions on day of transfer

[ivygrimes]

Hey all

Been doing my research and can see that particulary for a FET natural cycle (or otherwise), if using a 5 day blastocyst, it is recommended to transfer 5 days post-ovualtion.
However, many other pieces of research say it should be done on days 6-10 post ovulation. Does it make a difference whether this is a fresh or frozen cycle? Is it the same for non-IVF ladies? Is it all timed the same regardless of treatment, medicated or otherwise, or not?

When I ovulated on a Tuesday (with the help of digital ovulation sticks) my clinic booked me in 6 days later to transfer on a Monday. Not sure if this was because they're not open Sundays or whether it doesn't make too much difference whether 5 day embroys go in on 5th/6th or 7th day past ovulation. I was non-medicated BTW.

My other thought was, average ovulation lasts for up-to 24 hours so perhaps when I ovulated, they counted 5 days once I have finished ovulating on the Wednesday? Who knows?

I remember wondering why they didn't book me in to transfer the next day given I was ovulating but realised we already had 5 day frozen embryos!

Any thoughts and advice on this would be appreciated.

Ivy

[Pigletina]

Hi Ivy, I had a natural FET last time and spent a good long while stressing about ovulation timing etc. If you detected ovulation by peeing on a stick, that is detecting LH surge, not ovulation. It precedes ovulation by on average 24 hours, but the window is quite wide so you could ovulate anything between something like 16 and 48 hours after. My care clinic assumed 24 hours on average, so transfer 6 days after LH surge, which they hope is approximately 5 days after ovulation. But there is a lot of guess work. Other clinics, in non-covid times, would do a blood test for the LH surge which is more precise and confirm ovulation with a scan, but I didn’t have any of that. I was stressed and spoke to the consultant at the transfer, because I think I ovulated quite late in that time window, and she said the window of implantation is not that precise and varies from cycle to cycle and woman to woman so I shouldn’t worry about being 12 hours early or late or whatever. Not sure if knowing that makes it any less stressful though! Good luck with yours x

[ivygrimes]

Hi Pigletina

Thanks very much for your help and background to your experience.

I didn't realise the digi sticks were to detect surge and not ovulation. How silly I feel. Is this the case for all ovulation sticks or just clearblue?

I guess clinics can only really guess and estimate when it comes to natural cycles that are not assisted with medication.

[Pigletina]

It’s all urine tests i think! I think LH is the only thing that is detectable in wee that gives any indication of imminent ovulation. Yes you are right, it just gives the clinic a best guess about when ovulation will happen! I did find my natural cycle a bit stressful because of that, I was jealous of everyone on medicated cycles who knew exactly when everything would happen...