Does your girlfriend have regular periods? Did she take up some form of strict diet/exercise regimen recently? Or a night shift at work? All of these can cause delayed periods.
The chances of getting
pregnant in case of withdrawal method are low but not zero. The chances are also low if the act takes place a couple of days before the expected period- if all her previous periods are regular.
Next Steps
ultrasound pelvis and evaluation of hormones related to period disturbance-
TSH and PRL, before going for progesterone withdrawal therapy to regulate periods this cycle
Health Tips
Understand all contraceptive options and choose the best one to avoid such scares in the future.