Pregnancy does not start at conception. Once an egg is fertilized it can take around 6-10 days for that fertilized egg to then travel down the fallopian tube and to the uterus where it can then implant for pregnancy to occur. How long this takes can vary on factors such as where the egg is fertilized in the fallopian tube and overall health. Depending on where a woman is in her cycle pregnancy could occur anywhere from between 6-17 days after sex.