Can conceive pregnancy before 5 days period?

It's less likely right before your period because ovulation has usually passed, but sperm can live a few days so nothing is 100 percent. My doctor said cycles vary a lot, especially if irregular. If you're trying or avoiding, tracking ovulation is more reliable.

With PCOS my cycles were all over the place so the safe day theory never worked for me. Honestly it's hard to predict exactly. I'd say don't rely on calendar timing alone, talk to your gynac.