How often have you heard that a menstrual cycle should be 28 days and that ovulation usually occurs on Day 14? This is a myth, pure and simple. And yet it is so accepted that it's sadly responsible for countless unplanned pregnancies. Furthermore, it has prevented many couples who have desired a pregnancy from attaining one. Much of this fallacy is a legacy of the dangerously inaccurate Rhythm Method, which falsely assumes that individual women have cycle lengths that, if not precisely 28 days, are reliably consistent over time. The result is that Rhythm is nothing more
than a flawed statistical prediction using a mathematical formula based on the average of past cycles to predict future fertility. In reality, cycles vary tremendously among women and often within each
woman herself, though most cycle lengths are 24 to 36 days.

How often have you heard that a menstrual cycle should be 28 days and that ovulation usually occurs on Day 14?