It shouldn't, but each person reacts differently to certain foods. Look at what you are including in your Blast. To start, if including soy or maca, then I'd omit those to see if anything changes. Also, be sure you are getting enough calories and are not underweight. Stress and hormone-based birth control can also alter our menstrual cycle. If it continues, talk to your OB/GYN to ensure there's no underlying medical condition.