Hi,
Welcome to the ehealthforum and I am really glad to help you out. Your concern is regarding the status of your girlfriend’s pregnancy. Even if there was no ejaculation inside, yet sometimes there are active sperms in the prostatic secretions or precum which can cause pregnancy. But for this the semen needs to be ejaculated inside.
If she has missed her periods, then she should do a urine for pregnancy test or get a serum HCG test done from a gynecologist. It is more likely due to missed periods due to stress or other causes rather than pregnancy.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.