[Brandye]

They are addressing a rather esoteric situation. If you have had unprotected sex in the past week, there may be some live sperm still swimming around the uterus. Four days is a more likely case. There is really nothing to be done about this except be careful for the rest of the month and hope for a regular and normal period. This risk is real but not high.

Demon, as always, is correct. Please take her advice and read Caution: Take Only as Directed. Read the entire thread and you will have a better understanding of how the female body work. Perhaps she should read it as well.

Most women in stable relationships taking the pill use no other form of birth control. About three women of a hundred will become pregnant each year using the pill alone. Women not in permanent or married relationships should use condoms as well. The condom reduces the chance of disease transmission. The pill does not. And the combination of the pill plus condom gives protection that approaches nil as a risk.