Probability of pregnancy after unprotected intercourse by timing of coitus
Probability of pregnancy after unprotected intercourse by timing of coitus
3 days before ovulation
15 percent
1 or 2 days before ovulation
30 percent
Day of ovulation
12 percent
1 or 2 days after ovulation
Near zero
Adapted from: Trusell J, Rodríguez G, Ellertson C. New Estimates of the Effectiveness of the Yuzpe Regimen of Emergency Contraception. Contraception 1998; 57:363.