What Is a Fertile Window?

I've written many times about how ovulation can be quite hard to pinpoint. Since ovulation can occur at different times, your fertile window may be very hard to predict. Here is an article that talks about a women's "fertile window":

Egg Timer

From the article:

"A woman's six-day fertile window includes the five days prior to ovulation, plus the day of ovulation itself. Urine tests can reveal when ovulation has taken place - but there are no biochemical markers to indicate that a fertile window is opening.

Conventional wisdom holds that women are most likely to ovulate exactly mid-way through an average 28-day cycle. But this is wrong and the variation between cycles, and between women, is huge, says Allen Wilcox of the US National Institutes of Health"