almost a month that my girl friend did not have a period

Hi,
Welcome to ehealthforum.
Absence of period or missed period is associated with pregnancy. Sometimes periods are delayed by 5-10 days due to underlying hormonal changes, stress etc. Wait and watch for her periods. Look out for development of any new symptoms if pregnancy is suspected. She should visit her gynecologist for further evaluation and assistance if she does not get her periods within 10 days of expected period dates, or gets abnormal bleeding. If pregnancy gets ruled out and if you intend to remain sexually active, you should consider getting her started on suitable regular birth control measures to be protected (after her periods). She should be regular with birth control use as instructed. Avoid having unprotected sexual contact if you are not ready for pregnancy.
Take care.