To Bleed or Not to Bleed Series: Normal Is What?

Dr. Corner pondered this in the UK for us at the turn of the century, oh, I mean, the last turn. He studied menstrual cycles from 1910 to 1950, and concluded women have monthly periods (I'm paraphrasing here). But now, we have more accurate methods of science to put this question to the test. When do they begin, when do we ovulate, how long will the follicular or estrogen phase be, how long will the luteal (progesterone phase) be? First we ask a woman when her period starts (ok, I'm paraphrasing the "more scientific" part too, but they are using all sorts of fancy blood and urine tests once she raises her hand and says, ready to go). New conclusions from a Feb 2009 study published in Fertility and Sterility journal: normal cycles are not the 21 to 35 days that it says in my gyn text books, but 23 to 32 days. Although these researchers have only slightly tweaked average normal menstrual cycle length...used to be "every 28 days" now we can reliably say "every 27.7 days" according to the new study anyhow. And the ovulation: that can normally occur anywhere from day 10 to day 20. And then how long is the progesterone phase, that starts at ovulation and lasts 9 to 17 days. And if pregnant, when do eggs implant? I've always said, day 6 after ovulation, nope, accurate pregnancy testing put to the test here...can be any where from 5 to 14 days after the ovulatory window, in fact, about day 20 to 30 in most cycles. Confused? Write to the Gyno Gab Gal, I'll try to sort it out for you! xoxo