The high number of cycles in women today is considered abnormal by some and a result of modernization.
http://gladwell.com/john-rock-s-error/"the modern way of living represents an extraordinary change in female biology. Women are going out and becoming lawyers, doctors, presidents of countries. They need to understand that what we are trying to do isn't abnormal. It's just as normal as when someone hundreds of years ago had menarche at seventeen and had five babies and had three hundred fewer menstrual cycles than most women have today. The world is not the world it was."
"Dogon farmers, in many respects, live much as people of that region have lived since antiquity. Strassmann wanted to construct a precise reproductive profile of the women in the tribe, in order to understand what female biology might have been like in the millennia that preceded the modern age. In a way, Strassmann was trying to answer the same question about female biology that John Rock and the Catholic Church had struggled with in the early sixties: what is natural? Only, her sense of "natural" was not theological but evolutionary. In the era during which natural selection established the basic patterns of human biology–the natural history of our species–how often did women have children? How often did they menstruate? When did they reach puberty and menopause? What impact did breast-feeding have on ovulation?"
"Among the Dogon, she found, a woman, on average, has her first period at the age of sixteen and gives birth eight or nine times. From menarche, the onset of menstruation, to the age of twenty, she averages seven periods a year. Over the next decade and a half, from the age of twenty to the age of thirty-four, she spends so much time either pregnant or breast-feeding (which, among the Dogon, suppresses ovulation for an average of twenty months) that she averages only slightly more than one period per year. Then, from the age of thirty-five until menopause, at around fifty, as her fertility rapidly declines, she averages four menses a year. All told, Dogon women menstruate about a hundred times in their lives. (Those who survive early childhood typically live into their seventh or eighth decade.) By contrast, the average for contemporary Western women is somewhere between three hundred and fifty and four hundred times."
Second, some suspect the increased number of menstrual cycles accounts for the increase in breast cancer risk.
http://gladwell.com/john-rock-s-error/"some of the risks that go with the benefits of a woman getting educated and not getting pregnant all the time are breast cancer and ovarian cancer"
Lancet. 2012 Jun 23;379(9834):2322-3."In 1713, Italian physician Bernadino Ramazzini1 noted that
nuns had an extremely high incidence of that "accursed pest",
breast cancer. Today, the world's 94 790 nuns still pay a terrible
price for their chastity because they have a greatly increased risk
of breast, ovarian, and uterine cancers: the hazards of their nulliparity.
Fraumeni and colleagues2 compiled data for cancer mortality rates in
31 658 Catholic nuns in the USA between 1900 and 1954, and showed
that nuns had an increased probability of dying from breast,
ovarian, and uterine cancer compared with the general
population (figure). »
"MacMahon and colleagues3 were
the first investigators to make a formal link with parity,
showing, in 1970, that parous women had a decreased
risk of breast cancer compared with nulliparous women.
Parous women receive further protection if they have
their first child at a young age, bear more children, and
if they breastfeed. »
«
Nulliparous women have a higher number of ovulatory
menstrual cycles than do parous women because of the
absence of pregnancy and lactation, and an increased
number of cycles affects cancer risk."
Increased number of cycles = increased frequency of cell proliferation = increased risk of a mutation arising
Theoretical at this point but plausible.
Also, cycles increase the risk of mood swings and I have never come across the finding that cycling vs continuous produces better results.
Regarding the use of bio-identical progesterone, over the years, I have amassed extensive documentation and research findings confirming its negligible side-effects, several positive effects and showing that it does indeed promote extra growth in the breast tissue. If you want, I can send you this information privately and you can show it to your doctors.
