Originally Posted by
atomic sagebrush
I don't think that number of hours before positive OPK does anything any different for swaying at all so I will just wish you good luck and pink dust! 20 or 27 hours before pos OPK - both are of course going to be somewhat lower odds of conception. The good news (for conception, maybe not for your peace of mind though, sorry) is that a positive OPK does not come a "set" amount of time before O occurs. So one month you might have BD 20 hours before pos OPK but Oed 36 hours after pos, another month you might have BD 27 hours before pos OPK but then Oed only 24 hours after pos. Net result - about the same length of time, and no way of knowing.
It's hard on sperm with creamy CM but the good news is that the semen is like a little "life raft" that keeps them alive to get into the cervix where you very well may have more EWCM than you can see from outside.