Cycles Too Short

Q: Are short menstrual cycles a problem?

A: You first should determine if and when during the cycle ovulation happens. Polymenorrhea usually reflects irregularity of hormonal events coming from the ovaries, and it often means that you don't ovulate.
Polymenorrhea decreases your chance of conception because you don't ovulate, and even if you do ovulate, it happens very early in the cycle. In a 20-day cycle, ovulation can occur around CD 6, and if fertilization occurs, the endometrium, the lining of the uterus, is not ready yet for the implantation of the fertilized egg.