As far as STD's would be concerned it is never safe to have "unprotected" sex.
For risk of pregnancy, it depends upon EXACTLY when you ovulate. Normally that would be between about days 11 and 16 of your cycle.
If you have a short period, say less than 5 days, it is unlikely you'd get pregnant - but not impossible. Sperm can survive about 5 days - so that'd bring you to about day 10, prior to ovulation. No egg, you can't get pregnant.
There's always a risk though.
Hope it answers your question.
thank you for your reply really appreciate it.