There is not a common guideline at all clinics and all doctors. Previously a minimum of 8 mm used to be the norm for good results, but many clinics want to see above 7 mm. Of course some what 9 mm or more...it really depends on your RE. Recent research suggests anything below 7 mm has a lower change of outcome, though being lower than this does not mean that you won't get pregnant. As far as the measurement it is the measurement that you have BEFORE you start progesterone that is indicative of outcome as progesterone tends to reduce the thickness (to no detriment).
I am searching this thread and must not be awake yet because I am sure the answers are here somewhere. I know my lining thickness from cd12 was good.
What is the desired thickness as time of transfer?
Approx how much is the lining suppose to thicken per day upto transfer and does it slow down once on progesterone?