<s>[INST] Hi, I have used primolut n for 14 days and the last dose was on the 12th of Nov. My periods started on the 14th of Nov. i had irregular menses that is why my doctor prescribed this for me. Does this mean ill now be having shorter cycles now that this one was 23 days  and the previous ones were longer? Do i have to continue to take the drug every month to have a shorter and regular cycle and also for purposes of calculating my ovulation to become pregnant? [/INST] Hello dear,I understand your concern.In my opinion the primolut N is given for regularisation of menstrual cycle.This might be continued for 3-4 months so that furthur cycles will be regular.Even the duration of normal menstrual cycle varies from 21-35 days.So 23 days cycle is not considered as short.Also the causes for long periods like thyroid abnormalities,PCOD,overweight or obesity ,stress should be ruled out.Avoid stress if any.Weight reduction in case of overweight or obesity is also helpful.Best regards... </s>