When does premenstrual syndrome occur?

Premenstrual syndrome usually occurs in the days or weeks before a period and improves during or shortly after menstrual bleeding begins. The exact timing varies between people and from cycle to cycle. Symptoms may include cramps, bloating, breast tenderness, headaches, tiredness, food cravings, irritability, anxiety, or low mood. A recurring pattern is more informative than one isolated month.

PMS is linked to the menstrual cycle, so symptoms are expected to have a symptom-free or noticeably easier interval after they settle. If symptoms begin only after bleeding starts, continue for most of the month, or do not change with the cycle, another explanation may need consideration. Breast tenderness can occur before a period; the [Breast Pain](/symptoms/breast-pain/) page covers that symptom separately.

Use a calendar or phone note to record bleeding days, symptoms, severity, sleep, medicines, and the date each symptom improves. Bring the record to a clinician if the pattern is unclear or disruptive. Gentle activity, regular meals, hydration, warmth, and a steady sleep routine may make the premenstrual phase easier. If contraception is being considered, ask whether the [Combined Pill](/treatments/contraception-and-family-planning/combined-pill/) fits your circumstances.

Seek medical advice when symptoms interfere with normal life, appear at unexpected times, worsen suddenly, or remain after the period. Get urgent help for severe pain, fainting, fever, heavy unexpected bleeding, or thoughts of self-harm. A clinician can distinguish PMS from menstrual pain, pregnancy-related problems, or other physical and emotional conditions by reviewing the timeline and symptoms.

Does my symptom diary show a premenstrual pattern? When should I record symptoms? Could my symptoms be caused by something outside the menstrual cycle? What warning signs should prompt urgent care? Would treatment be useful during a specific part of my cycle?