Women need to understand when and how pregnancy begins to understand how EC can prevent pregnancy. Fertilization is not pregnancy. Becoming pregnant is not a single event but a series of events. This series of events usually takes between 8 and 10 days but can take up to 12 days after sex. Successful fertilization generally takes place on the day of ovulation.
Medical experts agree that pregnancy starts at implantation.
Nearly all pregnancies occur from intercourse sometime in the six-day period ending on the day of ovulation. Sperm can survive for up to 6 days. Therefore, even if you don't have sex on the day of ovulation, it is still possible to get pregnant from sex you had before ovulation. Timing of Sexual Intercourse In relation to ovulation. N Engl J. Med.