Timing of FET

[dogmam]

Hi, just looking for advice or experiences please.

I had my first round of IVF with ICSI in the summer but due to OHSS risk it was a freeze all cycle, of which we had 2, 5 day blasts frozen.

I had my first FET in September, which resulted in a positive test but a very early miscarriage/chemical, confirmed by hcg blood tests. Once it was confirmed, I stopped the progesterone and eastrogen and had a bleed a few days later. I then had my period about a month later and have started my next FET cycle.

I have been on estrogen tablets x3 daily since day 2 of my period (although to be honest I'm not really sure if it was day 2 because I always go from spotting to heavy then spotting again so never sure exactly). I went for my scan this week, which would have been cycle day 9, I think, but my lining was only 5mm so I'm now on estrogen tablets x4 daily and have another scan next Thursday which will be cycle day 17. My worry is that won't this be too late to then have transfer some time after this?

My cycles are uslly around 28 days. My first FET I started estrogen from day 2, progesterone from day 12 and had transfer on day 17. This time I won't have even started progesterone by day 17 as I will only be having scan.

Does anyone have any advice or experience? I did ask the clinic and the dr said it's fine when I transfer but I need to wait for my lining to be thick enough which I know but thought transfer was timed with ovulation?

Some people will take estradiol for weeks if needed, it doesn't make any difference, the important factor is how long you're on progesterone for, so there's no need to worry. You'll need to ideally have a lining of 8mm, but some clinics will be happy with 7mm. So you'll need some more time on the estradiol before the progesterone can start and the transfer can be scheduled in.

If there are issues with your lining thickening over the next few days and the cycle is cancelled (I hope not!) then you should arrange either a HSG or saline scan.

@Gardenlady543 thanks so much for the info. Yeah my lining was 7.6 last time, my clinic want anything over 7, so now that I know it doesn't matter when in the cycle I transfer, then I'm pleased to stay on the high dose for another week. I was just worried as I was thinking if I don't transfer until day 20 something then my cycle is only 28 days usually I was getting confused with how it all works.
With progesterone, should I be taking that for 4 days before transfer if it's a day 5 embryo, do you know?
I'm also having the Lubion injections this time aswell as the pessaries. Thanks again!

@dogmam you're having a fully medicated FET cycle so your natural cycle doesn't matter. The medications have basically switched off what your body would normally do, so you don't need to worry about that.

Normally you have a day 5 transfer on day 6 of progesterone.

Don't worry. While on estrogen you ovaries are supressed and the they are not producing any hormones. You can a have a longer cycle until the lining reaches the ideal size.

Thank you so much both, that makes sense now you have explained it.
My next thing to worry about is that my lining scan today was only 7mm, even after upping my estrogen to 4 a day for the last week or so, but my clinic are happy with this and have booked me in for my transfer next week, I thought 7mm was still pretty thin and lots of clinics will only transfer at 8mm+?