Ovulating on letrozole/ femara

I'm on letrozole CD 5-9 and trying to determine what day I ovulated (because silly me forgot to test).
Their website says it generally occurs CD 16-19 BUT that's with taking it on CD 3-7 (I did 5-9).
Is it simple math here? Does that mean I should have ovulated on CD 17-21?

I got a BFP today and now I'm trying to determine my conception date. I did BD on CD 11,14, and 18.

Also, today is CD 25. If I ovulated and conceived on CD 18, would that have even been enough time for it to register a BFP (takes around 5 days to implant??) plus time for hcg to build up. I took a "6 day sooner" 1st response test this morning.

Fingers crossed I have some pink dust growing in me!!!!

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I would guess you conceived from sex on CD 11 or 14 as day 18 would just be 7 days from your BFP which would be extremely rare even with an early response test. An 11dpo positive makes sense.

It's not super likely you conceived with the BD on CD 18 based on the earliness of the positive pregnancy test, but 7 DPO for a pregnancy test is possible, so if you ovulated on CD 18 and got pregnant that same day it is still in the realm of possible, just not super likely.

The suggested O dates on the website are just averages. Most people ovulate 5-10 days after their last dose (so that would be CD 14-19) and it's much more likely to be on the further end. It's pretty much impossble to O sooner than that 5 days after the last dose. The Femara blocks ovulation until the body can recover from taking it (which takes about 5 days)

So I find it pretty much impossible you conceived CD 11, although the sperm might have survived a few days.

Most likely is te CD 14.

But none of us can tell you when you ovulated, unfortunately. Just beyond our capability to know that.