Hi, Menstrual cycle consists of bleeding phase, ovulatory phase and secretory phase controlled by different hormones. Ovulatory phase is controlled by the hormone estrogen which helps in maturation of ovarian follicle. Secretory phase is controlled by the hormone progesterone. Ovulation, that is release of the egg from the follicle separates the phase. Upon fertilization of the egg, the zygote is formed which get implanted in the endometrium of the uterus and develops into embryo and then fetus. If the process of fertilization not happens, developing endometrium of the uterus shreds off along with the arterioles which leads to periods. Several factors disturbs the normal menstrual cycle such as obesity, diet pattern, drugs, hormonal disturbances, etc. Folic acid has no role in controlling the periodicity of menstruation. It is prescribed for the women in reproductive age group who are waiting for conception to prevent any defects in developing brain tissue. Consult your Obstetrician for irregular periods. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Pradeepraj, General & Family Physician