Since I enjoying working with women, I get to spend time talking with them about their periods. There are countless times when I ask them when their last period was and they do not know, because they don't keep track of it. You HAVE to keep track of your periods, ladies. Our monthly cycle can vary in so many ways from month to month that it is important to track what is happening with you. I recommend that you not only mark the starting date of your period, but also the ending date. Knowing your cycle is very important for understanding your fertility, you status in peri-menopause/menopause transition and the overall health of your body. For younger women knowing when your fertile time is vital if you do not want to or if you do want to get pregnant. It is just as important for peri-menopausal/menopausal women to know how many cycles they have skipped, as you are not considered post menopausal until you have gone an entire month without a period. Once you are considered post menopausal it is still important to bring it to a doctor's attention if you bleed.
I track my periods on Google Calendar, I often recommend that patients find the easiest way for them to track them, either using their "crack-berries", online somewhere, or even an "old fashion" wall calendar. It is vital to write down the beginning and the end of your period, equally important is to write down color, clots, number of tampons/pads you are using along with any discharges you have throughout the month. This information, allows the doctor to better understand your cycle and help with any issues. Ladies please, please start to track your periods, if you already are, make sure you are writing down as much information as you can. We need to know our bodies, so that when things start changing we know what is going on.