When checking CM for egg white consistency – how long after sex will it be a true test of fertility?

If you have egg white CM, you need to begin the intercourse phase. You are most fertile BEFORE you ovulate so make sure and block a certain amount of days for intercourse. I have typically had the rule of thumb, starting on cycle day 10 through cycle day 17.

I reread your question and I think what your asking is when do you show CM that is eggwhite. Typically it’s the day before ovulation. It has nothing to do with the intercourse and the other “body fluids” I usually notice it after I pee. (sorry lack of a better word)
Bottom line, if you are having intercourse anytime you have CM that is eggwhite consistency (unrelated to sex) you are fertile and ready to get busy!

Hope I helped and baby dust to you!

It’s best to test before sex. They say 8 hrs but I’ve had semen still there after 12 hrs. I knew it wasn’t cm due to my cycle day (too early for fertile window). Semen can look like stretchy egg white (slightly thicker though). Sorry for TMI
You can also remove the semen by douche with water (just wait 30 mins after sex) then wait 4-6 hours to test cm.
You’ll also notice the cervix is softer and open at the tip when you have egg white cm (EWCM).