hi, thanks for choosing hcm, dupahaston 10 mg is taken from day 15 to day 25 1 tablet daily so that pregnancy due to progesterone deficiency continues as this supplements or if pregnancy did not occur it causes withdrawl bleeding to occur aiding in regularising your periods and withdrawl bleeding need not be a full flow or heavy flow,it can last for very less time and less quantity also sometimes only spotting is seen you didi not mention your age and marital status so if you are married and had intercourse go fo a pregnancy check up and if positive meet your doctor if not you can go with this medication even in the next month counting 22nd july as your period date reduce weight if you are obese,this almost clears your hormonal deficiencies and irregular periods hope i answered all your queries feel free to contact me for further queries thank you