Hy sir last month me and my gf had sex on 12 february and we used condom during the act. Her date for occurrence of periods is on 1 march but still she has not attained her periods, we do pregnancy check with test kit by using second urine of day as sample and it shows negative results for pregnancy, so please kindly guide for this problem. Is there any chance of pregnancy? Please tell what to do to induce periods? Also she's taking levocetirizine from a month because of her skin reactions and recently three days back she has taken cephalexin which cause her urticaria as side effect. Please reply as soon as possible.