How many weeks after sex can pregnant be detected on a pelvic ultrasound? got a regular period this month, neg test but still want to rule out

See doctor: Check with your doctor to find out if further tests are needed. May be unnecessary to get further tests. Look into measures to prevent unwanted pregnancy.

Already ruled out: One pregnancy test done correctly, with a negative result, means not pregnant (but a second test can be done a week later if still worried). A normal, regular menstrual period means not pregnant, so a period plus a negative pregnancy test combined means no more testing is needed, unless more unprotected sex is happening (which could have created a new pregnancy after the last test ; last period).