Late period no pms symptoms negative test. is she pregnant?

Unlikely : If she followed the package directions and her period is already late, she is unlikely pregnant. Home pregnancy tests are very accurate. If there is still no period and she rechecks in 3-4 days with a first morning urine, you can be extra certain.

Not likley.: Reasons for missed /late periods: low body weight, obesity, marked weight gain or loss, over-exercise such as in endurance athletes, breast-feeding, stress, illness, eating disorders (bulimia or anorexia), travel, hormone irregularities, drug use, medications (i.e., birth control) or med problem (polycystic ovary syndrome or Asherman’s syndrome. #1 reason is pregnancy.