But Why is My Progesterone Low?

I've seen it a hundred times. Heck, I've experienced it myself. The lab results come in, you're told your progesterone is low, and you get a brand new, shiny prescription for... progesterone. As a someone who will testify to the fact that progesterone supplementation was instrumental in treating my infertility, has saved multiple of my pregnancies, and combats my PMS symptoms, I am not going to advocate that doctors stop prescribing it. But, being the (as you clearly know by now) crunchy individual that I am, it wasn't long before I started asking "but why is my progesterone low?" It's the same question many of my clients ask. So let's explore some possibilities.

Over the years, I've heard many explanations/theories for the causes of low progesterone. The most common I've run across is estrogen dominance. And while estrogen dominance is a real thing, I am personally not convinced that it's quite as simple as many make it out to be. And I'm also not convinced that it is the cause. So what is estrogen dominance? I suppose it depends on who you ask. The reality is that there isn't actually a diagnosis code that doctor's use when billing insurance for it like there is for Polycystic Ovarian Syndrome (PCOS - E28.2) or hypothyroidism (E03.9). So there is a little bit of wiggle room when determining what it is. Essentially, it is when a woman has too much estrogen relevant to progesterone. If a woman has a higher than normal level of estrogen compared to her progesterone, then she is considered "estrogen dominant." Using this type of analysis, a woman with normal levels of estrogen, but low progesterone, is considered estrogen dominant. So is a woman with normal levels of progesterone, but really high levels of estrogen. To further complicate the matter, a woman with very low levels of both estrogen and progesterone is not estrogen dominant if the ratio between the two is normal. Likewise if she has really high estrogen and progesterone, but the ratio is in the normal range, she's not technically estrogen dominant. Sheesh. This makes for quite a quandary when someone says "estrogen dominance causes low progesterone" because it appears that the two are absolutely related, but not exactly in the way people think. Is one hormone causing the other to be whacky or is something causing dysregulation in both? The jury is still out. But so far the science leans towards both are actually affected by something else. So instead of throwing up our hands and throwing progesterone at estrogen dominance, maybe we should be asking "but why do I have estrogen dominance?" and then try to fix that.

As an aside, many times a woman is told she has high or low estrogen or progesterone with only a single blood draw at any old random time in her cycle. Just today, in fact, I consulted with a woman (who is perimenopausal) who told me she was diagnosed with low estrogen by her OBGYN after only one blood draw despite also having PCOS. After a fair bit of investigating I discovered that her blood was drawn on day 3 of her cycle when estrogen is supposed to be very low and it was in the normal reference range for a woman her age. I suggested she speak to a NaPRO doctor and have cycle targeted blood draws for her hormones. All of this is to say that estrogen dominance is a real issue, but I don't think that the criteria to diagnose it is universal and I think the methods used to make these decisions are often less than ideal (to put it politely).

Ok, back to what causes low progesterone. It appears that estrogen and progesterone dysregulation are linked. And we all remember me geeking out on parabens, bisphenols, and glyphosate in relation to sperm health. Well, it turns out all those things cause hormone dysregulation in women too. And while I can, and often do, go down the rabbit hole of endocrine disrupters, I'll keep this short for you today and give you some quick things that could be causing your low progesterone (other than estrogen).

1. Thyroid Disorders - That's right. Culprit number one is thyroid disorder. But before you say "I had that checked, and my doctor says it's normal," keep reading. First, thyroid function is a tricky thing to assess and most doctors are simple not trained to do it. For the most part, they only check one thyroid hormone, TSH (or maybe T4 if you're lucky). But along with TSH and T4 there is T3, Reverse T3, Free T4, Free T3, several ratios of those hormones, and some autoantibodies that can be checked. But most doctors (even endocrinologists) don't check these or know how to interpret the results. Further, the reference range for TSH is typically up to 4.5 at most labs and an abundance of research over the past decade really shows that a TSH reference ranges should be adjusted for age and sex and that 4.5 is too high for most women of child bearing age. All of this is to say that if you've been told your thyroid is "normal," then you might want to get a second opinion from someone who really knows what they're talking about. I have seen miraculous changes in charts and progesterone levels when a woman addresses her "normal" thyroid by taking thyroid medication.

2. Chronic Stress - If you're consistently under stress, then your body is consistently in fight or flight mode. And if your body is in fight or flight mode, then it's not worried about you getting pregnant, or even digesting, it's worried about saving your life. So all those hormones related to the menstrual cycle are not the body's priority in times of stress. But there's the caveat-your body doesn't know if you're being chased by a tiger or if your email inbox has 123 unread messages. Cortisol and adrenaline appear for both. And too much of those over and over again can seriously dysregulate your sex hormones. I like to call hormones you cannot live without (adrenaline, insulin, etc...) primary hormones. If these hormones are dysregulated, then the body won't go to the trouble of regulating your secondary hormones (estrogen, progesterone, etc...) because they aren't as important as the primary hormones. Even if you think you're not stressed out, take an inventory of your daily activities and really assess if that's true.

3. Gut Dysbiosis - More research emerges daily on the function of the various bacteria living in your gut. The fascinating ecosystem living in your gut, called your microbiome, plays a crucial role in your well being. The various good bacteria (that we call probiotics) help regulate your hormones, prevent diseases and cancer, and overall are the most ignored part of our health-in my opinion. I have read an inordinate number of books and journal articles on the topic. If you want a really good overview and the ability to determine if you might have gut dysbiosis related hormone dysfunction, I'd recommend Gut Check by Dr. Steven R. Gundry (we are in no way affiliated with Dr. Gundry, I just happen to think he has the most comprehensive book on the matter).

While I know I didn't answer why your progesterone is low, I did give you some good places to start looking. And if you're wondering if you do have low progesterone, contact one of our practitioners today to start charting with the Creighton Model FertilityCare System (CrMS). CrMS teachers are specially trained to work with you to help you determine if you are at risk for low progesterone, thyroid dysfunction, estrogen dysregulation and other gynecologic issues.