Period ended yesterday and had sex today is there a possibility she can turn out to be prego?

Unlikely but risky!: Your period usually ends on around day 5 of your menstrual cycle and you don't usually ovulate until about day 14 and so the likelihood that this sperm will carry over and survive when you ovulate is highly unlikely. But why risk pregnancy? Get on a long acting contraceptive so these questions never come up. Consider an iud or an implant in the arm. :).