My last menstrual cycle was on January 22. When should the next start?

The average menstrual cycle lasts 28 days, but it can vary from 21 to 35 days. If your last menstrual cycle started on January 22, then the next one is expected to start on February 19 (28 days later). It is normal for menstrual cycles to fluctuate a bit. However, if your next cycle starts more than 7 days earlier or later than February 19, you should consider talking to your doctor.