<prompt> Side effects of oral contraceptives are all EXCEPT:Irregular bleedingHeadacheThrombosisIncreased risk of ovarian cancer  <response>: Irregular bleeding or amenorrhoea can occur if oral contraceptives are given continuously. Estrogen can cause headache, thrombosis and endometrial carcinoma. OCP decrease the risk of ovarian cancer REF.Essentials of Pharmacology TD TRIPATHI 6th EDITION page no 309 