When it comes to talk about perimenopause, you’ll most often hear about estrogen. And there’s a reason why.
There has been significantly more research (meaning money and time) devoted to estrogen compared to any other female hormone.
Before we discuss what we do (and don’t) know about estrogen, let’s make sure we understand what estrogen is.
There are a few main forms of estrogen: estradiol, estrone, and estriol. Estradiol (es-tra-die-ol) is the predominant hormone during years of fertility. During pregnancy, estriol (es-tree-ol) takes over. And in menopause and beyond, we have predominantly estrone (es-trone).
These estrogens are made in different parts of the body which helps to differentiate them. Estradiol is formed mainly in the ovaries, estriol comes from the placenta, and estrone from the adrenal glands. To make matters more complicated, estradiol and estrone can be converted to one another.
Since estradiol is significantly more potent than estrone and estriol, the vast majority of estrogen research has been done on estradiol. This is also why, if someone undergoes hormone replacement therapy (HRT), the estradiol form is prescribed. For this article, I will be using term estrogen but am I generally referring to estradiol specifically.
When it comes to your cycle, estrogen is responsible for regrowth of the lining of your uterus, the endometrial tissue that is shed during each period. It not only stimulates the growth of those cells but also the growth of blood vessels supplying nutrients to the endometrium.
Also important to note, estrogen stimulates those same cells to produce receptors for progesterone, which is getting the uterus ready for the second half of the cycle.
So where is estrogen coming from exactly? As I mentioned before, estradiol is made in the ovaries but specifically from our follicles. A follicle is essentially a multi-celled house surrounding the egg that helps it grow and develop. Without eggs and the surrounding follicles, we wouldn’t be making estradiol.
While estrogen is the predominant female hormone during the first half of your cycle, it’s not as though estrogen stops being produced. Estrogen is still present during the second half of the cycle as well, but progesterone has a bigger role to play during this phase.
So, what about the benefits of estrogen outside of the uterus?
You have receptors for estrogen all over your body including skin, blood vessels, and even your brain, which is why that drop in estrogen can cause a lot of changes to occur.
Specifically, estrogen has been shown to help promote healthy cholesterol levels and is generally thought to be protective for our heart and blood vessels, thus lowering the incidence of heart disease. Estrogen also stimulates skeletal growth, which may be why osteoporosis is more common in women after menopause.
Estrogen affects coordination, mood, and memory. In fact, more and more research is being done on the protective benefits of estrogen in the brain with investigation into possible therapeutic use for diseases like Alzheimers, Parkinson’s, schizophrenia, and even strokes.
In addition, with the brain being exposed to more estrogen, it explains why women’s brains are generally more adept at speaking and writing, fine motor skills, and speed and accuracy.
Estrogen is also similar to a hormone called aldosterone. Aldosterone is produced by your adrenal glands when you’re dehydrated or have low salt to cause your body to retain more salt and thereby retain more water. So, estrogen acts like a salt-retaining hormone (think PMS bloating).
Estrogen has also been linked with increasing satiety and reducing appetite as well as sensitizing insulin. And let’s not forget about its effects on hair and collagen growth (hello wrinkles) and helping to maintain your skins moisture.
The effects of estrogen are, suffice it to say, profound, which is one of the reasons why perimenopause can be so tumultuous.
But guess what? We just think estrogen is to blame for all our symptoms because that’s been the primary focus of research. For example, cholesterol and heart disease has to take into account insulin levels, hs-CRP, thyroid health and more so we cannot blame some of these complex diseases on one hormone. The same is true for perimenopause.
You are more than just estrogen and anyone that blames estrogen for health issues or treats perimenopausal symptoms with estrogen alone is misguided.
We’ll talk more next time about estrogen’s equally important (though significantly under-researched) counterpart: progesterone.