Hi welcome to health care magic... The oral contraceptive pill inhibit our natural hormone and prevent pregnancy... But as body adopt to new hormonal balance breakthrough bleeding can occur.... If bleeding more than switch over to another pill needed for control of bleeding... Physical examination also necessary along with pelvic examination to rule out organic cause or infection of genital tract, as pill can t prevent sexual transmitted infection.. So if needed vaginal swab can be taken.. According to examination further work up done... Take care Advise :Consult gynecologist and discuss your case along with physical examination...