Hello Doctor, I am 32 years old. For the last 3–4 months, I have noticed a pattern in my menstrual cycles. One month, my periods are completely normal with normal bleeding. The next month, the bleeding is very light. On the first day, I do not even fill one sanitary pad, the second day is also light, and by the third day, the bleeding almost stops. My periods are coming on time, and I do not have severe pain or cramps. My recent reports show: Hemoglobin :12.5 TSH: 4.96 µIU/mL T3 and T4: Normal Vitamin D: 19.26 ng/mL (Deficient) Vitamin B12: 253 pg/mL Testosterone: Normal Could this pattern be due to a hormonal imbalance, thyroid, or PCOS? Would you recommend a pelvic ultrasound and any additional hormone tests (such as prolactin, LH/FSH, or AMH if needed)?