Hi, Some of the side effects you are having, like irregular vaginal bleeding or breast tenderness may definitely be there with Postinor 2 tablets, which are usually of transient type and go by themselves with time. Frequency of cervical cancer is not increased with birth control pills, if used for a short period to be precise, more than 5 years. However, after a use of more than 5 years, a some what increased frequency of cervical cancer may be seen in women using these. However, after stoppage of use of these drug, this risk also starts to decline with time. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Satnarain Bansal, General & Family Physician