Menstruation delayed by a week, early pregnancy test paper shows negative, am I not pregnant?

Patient's question:

No

Doctor's answer:

Having sex without contraception cannot be ruled out as a possibility of pregnancy. Women are advised to use a pregnancy test kit first if their period is delayed by more than 7 days. Generally, if the period is delayed by more than a week, it is possible to determine whether one is pregnant, as fertilization usually takes 6-8 days to implant. If you had intercourse during your ovulation period, you can have a pregnancy test at the hospital 7 days after your period is delayed, which is the most accurate method.