Hello,
Welcome to ehealthforum
Pull out method is the most risky method and carries a high risk of pregnancy.It has already been two months that her periods are delayed.There is no point in waiting and get a Blood hcg test for pregnancy determination as it is a confirmatory test.
If her periods ae always irregular she needs a detailed evaluation for that also as it could be indicative of underlying abnormalities as ovarian cyst,pelvic infection,cervicitis etc.
Kindly visit a Gynaecologist for evaluation and precise diagnosis.
Take care!