Hello, Any delay in periods warrants a urinary pregnancy test. Duphaston and other hormones may cause irregular bleeding but a pregnancy needs to be ruled out first. If the pregnancy test is negative then you are reassured and very likely your periods will come within the next month. If you have PCOS, the periods may be very sporadic and irregular. To have regular periods you may get oral combined contraceptives or if you want to conceive you may use Clomifene to stimulate ovulation. I hope this answers your query. I remain at your disposal in case further medical assistance is needed. Regards, Dr. Antoneta Zotaj, General & Family Physician