TTC girl, avoiding big O, for how long?

Hi everyone,

I have been lurking on this board for a while now and dh and I are finally moving forward with a very low-tech TTc girl -- i.e. watching ph (around 4.5), missionary, shallow and no big O and hoping for the best....

From what I have read, when ttc a girl you are supposed to avoid the big O because it affects your internal ph level -- so I have avoided it during and after bd -- the question is, how long do you need to avoid the big O? Considering that fertilization does not happen immediately, do you need to wait until a few days past ovulation to resume regular (protected) activities? In other words -- is the ph critical during bd, or even after and for how long?

Thanks,

Michelle