Flank pain during a period

Period cramps usually begin in the lower abdomen or pelvis, but pain can spread to the back and sides. Flank pain that follows the same pattern each cycle and settles with your usual menstrual measures may fit referred period pain. A kidney infection commonly presents with flank pain and may also cause fever, chills, nausea or urinary changes. Kidney stones can cause one-sided, wave-like pain that may travel toward the groin, while a urinary tract infection may cause painful or frequent urination. Muscles, bowel symptoms and conditions affecting pelvic organs can also overlap with period pain.

Track the timing of the flank pain against bleeding, cramps, urination, bowel movements and activity. Gentle heat and rest may help familiar period-related discomfort; stop if they worsen symptoms. Take pain relief only if it is suitable for you, especially if you might be pregnant, have kidney disease, stomach ulcers or take regular medicines. Arrange a medical review if the pain is new, one-sided, severe, lasts beyond the period or returns with each cycle. A clinician can assess both urinary and menstrual explanations.

Seek urgent care for severe or sudden pain, fainting, repeated vomiting, a rigid or swollen abdomen, heavy bleeding, blood in the urine, or inability to pass urine. Fever or chills with flank pain need prompt assessment because they can accompany kidney infection. Get urgent advice for pain during a possible pregnancy, particularly with bleeding, dizziness or shoulder-tip pain.

Does the timing suggest menstrual pain or another cause? Should my urine be tested? Could medicines or contraception affect the pattern? What symptoms would require urgent care during a future period?