Updated: Mar 12, 2019
The next hormonal modifier I want to address is obesity, focusing here on the negative hormonal changes that occur as body fat levels increase. It's important to realize that, in some cases, the presence of the hormonal modifier may be causing a woman's predisposition to obesity. PCOS is a common one and it's overall effects on a woman's physiology, especially combined with the modern diet and lifestyle, put woman at risk for fat gain to begin with and this becomes a vicious cycle where PCOS causes insulin resistance which causes the PCOS to worsen, worsening the insulin resistance, etc. But even when PCOS or another hormonal modifier is not present, as women begin to gain excessive amounts of fat, there are a variety of hormonal changes that start to occur and much of this is due to the development of insulin resistance. Both progesterone and estrogen levels may go up and the production of androgens may increase as well creating a state of elevated testosterone/androgen levels, causing a PCOS-like state.
Obesity, like PCOS, is also associated with infertility and other pregnancy related problems. Ovulation may be impaired, the risk of miscarriage is increased and this is all fundamentally related to the hormonal changes that occur, and primarily the insulin resistance that tends to develop. For women wanting to become pregnant, this presents a problem but, as with PCOS, the loss of even moderate amounts of weight/fat drastically improves the situation.
Overall, increasing levels of body fat create an androgen-like physiology and the insulin resistance that will usually be present will create an effective luteal phase physiology.
Age Related Changes in Women's Physiology
In addition to the above modifiers, which can occur at any age in women, there are also a number of age-related changes that occur in a woman's physiology over her lifespan. Here I am only focusing on those changes that occur later in life such as peri-menopause and menopause itself. At perimenopause, a woman's reproductive function begins to decrease, a process referred to as the climacteric. Effectively, a woman runs out of potential follicles/eggs to fertilize and this signals the reproductive system to shut down at which point her estrogen and progesterone production is nearly eliminated. This is yet another place where women and men differ significantly. As I discussed in earlier blogs, with increasing age a man's testosterone levels are reduced (which some are calling andropause to liken it to menopause) but at no point does it drop to zero. In contrast, at menopause, a woman's reproductive hormone production essentially stops.
Regardless, the menopausal transition that a woman undergoes has a profound impact on her overall physiology although this is another area of some complexity as there are four different situations that have to be considered. These include perimenopause, the time before true menopause occurs which has both an early and late phase along with menopause itself. After menopause, women who go on Hormone Replacement Therapy (HRT) show a different physiology than those women who do not. I should mention that in addition to the profound changes that are occurring in a woman's hormones at this time, there are other changes that are simply age-related that also contribute to the changes in physiology.
Perimenopause literally means near menopause and refers to the changes that occur as a woman begins the transition into menopause itself. While perimenopause is typically thought to occur in the 50's, it is possible for some women to enter peri-menopause in their 40's or even 30's. The entire perimenopausal period can last anywhere from 12 months up to four years and is divided into an early- and late-phase depending on the specific hormonal profile which is seen. Unfortunately, only blood work to determine the actual levels of estrogen and progesterone can pinpoint exactly where a woman is at this time. During perimenopause, cycles may become infrequent or change in length and some cycles will be anovulatory with no egg being released.
If there is a perceived "benefit" to peri-menopause it's that falling estrogen may decreases PMS symptoms. At the same time, other symptoms, similar to what is seen postmenopausally often appear. Hot flashes, sleep problems, mood changes, a decline in sexual interest and function and a loss of bone density may all occur. The occurrence of these symptoms, especially the easily observable ones, can actually act as an indicator that peri-menopause has started; blood work would support or confirm this.
In early perimenopause estrogen levels can start to shift up and down but there is typically a decrease in progesterone without much change in estrogen levels. For that reason, I will consider early peri- menopause to be an estrogen-like situation, creating an effectively follicular-phase physiology. In late perimenopause, estrogen starts to drop along with the drop in progesterone and this will create a state of relative hyperandrogeni