I used to have a very regular monthly rhythm of 28 days, but the last months my cycles varies from 28 day to 16 and sometimes 14 days. (nicolejardim.com)
What they don't tell you is that you will be paying between $ 18 and $ 50 more per 6 - month cycle in the form of monthly assessed installment fees. (autos.com)
However, after 12 months the cycles became irregular in several of the exposed animals. (sciencedaily.com)