If the period between each two menstrual cycles is three months, does she observe the waiting period by months?

Question:
Peace be upon you, Your Eminence, father. The questioner says: If the period between each two menstrual cycles is three months due to the delay of menstruation in her case, does the ruling apply to her?

Answer:
No, as long as she menstruates, she does not observe the waiting period by months, but only by menstruation, even if her custom is delayed. Menstruation is necessary.