I got preggy this last time with one follie. I had maybe 2 smaller (not even close to mature) and we didn't do IUI just HCG trigger and timed BD.
I had a few cycles that I only had one and it didn't work but the first IUI I ever did had one and got preggy (that ended up a blighted ovum).
My RE only did progesterone 7diui/dpo.

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