There’s a certain irony in the fact that the majority of women have at one time or other probably experienced mild panic when their period was a few days late, only to discover that years later, so many of them would do anything to get pregnant. Both situations are really two sides of the same coin, and the bottom line is that if women learned how to chart their cycles, they would be able to understand what was going on with their bodies.

One of the most challenging menstrual patterns are irregular or long cycles. There are many reasons why a woman may have these, or why they may even not ovulate altogether. In fact, most women go through various phases in which they may experience such cycles, including adolescence, coming off the pill, breastfeeding, and premenopause. And there are also many conditions which may cause irregular cycles, including PCOS or thyroid problems.

But unless you chart, you may continually think that you are pregnant when you are not. If you are charting, there are two ways to tell the difference between pregnancy and just a long cycle:

• You are likely pregnant if you have more than 18 consecutive days of high temperatures above the coverline, especially if you also experience tender breasts and nausea.

• You are probably not pregnant if your temperature pattern shows consistently low temperatures, or a delayed ovulation that indicates that you are merely having a long cycle.