It is not necessarily normal to have a menstrual cycle of 52 days without any signs of menstruation. If pregnancy tests have been recently taken with morning urine and have come back negative, it may be best to consult a doctor to further investigate the cause of the prolonged cycle. False negative results on pharmacy-bought pregnancy tests are uncommon but possible, so a blood test prescribed by a doctor is the most reliable way to confirm pregnancy. It is important to seek medical advice for a thorough evaluation and appropriate management.