Hello, and I hope I can help you today. If you last had your period on September 12th, and today is October 5th, your period is not yet late for October. Most women have a 25-35 day cycle, so until you actually miss your period for October, there is no reason to assume you are pregnant. The folic acid and zinc you are taking are just extra vitamins that provide health to a growing pregnancy; these should not affect or change your menstrual cycle or it s symptoms. If your period is late in October, you should purchase and perform an over-the-counter pregnancy test. Modern pregnancy tests are very accurate and can be positive even 10 days after conception. If you do find out you are pregnant, there is nothing that needs to be done immediately as pregnancy is not a disease- it is a normal state for women in the reproductive phase of their lives. So it is important only to keep taking your vitamins, get plenty of rest, eat a balanced diet and avoid alcohol, caffeine and drugs. If your period is mate but you are not pregnant, the delay in your cycle can have a number of causes, including hormonal imbalances, certain medical conditions like thyroid disease, and even the stress of worrying about pregnancy. If you miss more than 2 months of your cycle (no bleeding for 3 months) and your pregnancy test is negative, you should see a physician for a hormonal evaluation. So in summary, a late menstrual cycle can be caused by pregnancy but there are other causes as well. I suggest you perform a pregnancy test if you are late, and if it is negative, try to be patient and you will likely get it before another month goes by. I hope I was able to adequately answer your question today and that my advice was helpful. Best wishes, Dr. Brown