I am writing this because so many women come here freaking out about what they “think” are “blood clots” during their period. I just really have to clear this up once and for all. It is normal for women to pass thick clumps of tissue during menstrual cycles. These clumps are NOT blood clots and nothing to worry about. They are, in fact, clumps of the uterine lining tissue which is shed during the period. Your hormones determine how thick your uterine lining will be each month. The thicker the lining, the more clumps you will have and the bigger they will be. I can see that you might confuse these with blood clots, but trust me, they are not. I personally took this question up with a gynecologist. So, if you have these clumps during your period, don”t worry about it. It”s normal! Annnnnd…. some months you might have them and some you might not. The fluctuating is not an indication of a problem.