What are the chances of getting pregnant after unprotected sex?

20% at most: If you and the man are the 2 most fertile folks on the planet, and you had unprotected sex at the time of ovulation, you have about a 1 in 5 chance on conceiving.

Varies.: Pregnancy can occur even with "protected" sex. If you do not desire pregnancy talk with a doctor about options of birth control.

Age-dependent.: Your age is a major determinant; the chance may be as high as 25% in your teens and twenties, but decreases to <5% after 40. It also depends on when during your cycle you have vaginal intercourse; most likely to conceive around 10-16 days after the first day of your last period (assuming regular 28-day cycles).

Age-dependent.: Your age is a major determinant; the chance may be as high as 25-30% in your teens and twenties, but decreases to.