Hello dear I understand your concern Plan B pill contain high progesterone. It cause relaxation of smooth muscle of the urinary tract and cause urinary stasis and ureter dilation in some case. So plan B pill could be a reason of the UTI. I would suggest to consult the primary care physician and undergo urine tests to confirm the UTI. Doctor will give following advices for UTI: Tablet nitrozoilum Tablet pyridium, syrup cital Drink plenty of water and juice of cranberry, orange and pineapple Maintain proper pelvic hygiene by using V Vaginal plus wash Hope this may help you Contact HCM for further health query Best regards Dr. Sagar