Hello, and I hope I can help you today.
First of all, if your girlfriend is taking birth control and you never ejaculated inside her, it is really not possible that she is pregnant.
A woman can occasionally have a delayed cycle or miss a menstrual period for a number of reasons- as a side effect of her birth control (especially if she missed any pills), weight changes, travel or alteration in her sleep schedule, or
stress (including the stress of worrying about
pregnancy). It can also be caused by certain medical conditions and
hormonal problems. Most of the time the cycle will return to normal after she finally gets her period, which may even be next month.
If she continues not to menstruate for a total of three months, she should see her GYN doctor as she should have an evaluation to rule out hormonal and medical causes of her delayed period.
I hope I was adequately answer your question today and that this information was helpful.
Best wishes,
Dr. Brown