The tale of 4 hormones – Irregular Menstrual cycle / PCOS

by SI on September 20, 2010

To understand how the hormone imbalance affects the PCOS menstrual cycle, some background about how the normal menstrual works will be helpful. You can find that article here – The tale of 4 hormones : Normal Menstrual cycle.

We saw that there were 4 main players in regulating the menstrual cycle. Two of them from the pituitary glands (Gonadotropins) and two from the ovaries (Ovarian or sex hormones).

  1. FSH (Follicle Stimulating hormone) to mature the follicles
  2. LH (Luteinizing hormone) that causes the ovulation
  3. Estrogen that controls the LH surge by a feedback regulation mechanism. It also prepares the uterus by thickening the lining.
  4. Progesterone has a negative feedback with LH and FSH, prepares the uterus for implantation, maintains uterine lining and drop in progesterone along with estrogen causes menstruation.

Hormones in normal menstrual cycle

This is how the levels of these will look like in a normal cycle.

What happens menstrual cycle hormone ovary basal body Uterus

What happens to these hormones with PCOS?

Basically they are go haywire. I will talk in detail about “why” they go crazy for people with PCOS in another post, but for now we will concentrate on “how” they look like. This is what happens to each of the hormones.

  1. Follicle Stimulating hormone : Low levels of follicle stimulating hormone (FSH), so the follicles (and in turn eggs) are underdeveloped. The surface of the ovary looks lumpy and bumpy with many semi-matured follicles just below the surface, all having failed to ovulate – usually they are arranged in a pearl-necklace formation.
  2. Luteinizing hormone : Constantly high level of Luteinizing hormone, instead of the mid-cycle surge. A surge in LH is required for ovulation, so a lack of it prevents us from ovulating.
  3. Estrogen : This hormone should also increase just before ovulation, but for PCOS women it remains constant. For some, it remains high, for some low. But the point is, it remains at a constant level.
  4. Progesterone : If you remember from the previous regular menstrual cycle post, progesterone is produced by the Corpus Luteum, the empty follicle after the ovulation occurs. For us, the egg never pops out, which means the follicle is not empty, so basically no progesterone is produced. Progesterone is not only important with menstruation, but it plays a role in several other processes.

For us the hormone levels would look like this –

What happens pcos menstrual cycle hormone ovary basal body Uterus

A lot of the symptoms we see with PCOS are a collection of symptoms arising due to the imbalance of each of these hormones. For example, mood changes, anxiety, depression, weight gain, irregular periods, headache, migraine, infertility, miscarriage, premenstrual syndrome (PMS), post partum depression, endometriosis  are some of the medical conditions associated with reduced progesterone production. Increased Estrogen stimulates breast tissue which results in fibrocystic breasts. Estrogen also increases body fat.

Introducing a new player – the male hormone

Not only do the hormones we need go out of control with PCOS, but due to the imbalance of the main players, our body introduces other players that we don’t need as well – Androgens, especially Testosterone. Yes, the male hormone. Even though they are called “male” hormones, Androgens are present in both male and female systems, just in differing levels. In men they are at a much higher level than women.

Imbalance of our regular players in the ovaries (LH, FSH, Estrogen & Progesterone) causes the ovaries to produce too much Testosterone. This guy is the culprit responsible for hiding our beauty underneath all the acne, hair growth and the weight gain that just won’t come off.

Now I hope you can understand a little bit about the hormones that cause all hell in our body. We will be revisiting these peeps again and again when we talk in detail  about different symptoms and treatment options.

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{ 5 comments… read them below or add one }

Nona Hayden September 20, 2010 at 2:04 pm

that helped, thanks


Hormone Imbalance October 29, 2010 at 3:09 am

We need also to take into account age-related changes alter the balance of sex hormones. Sex hormone imbalance closely resembles those of hypothyroidism and thyroid hormone resistance.


EndoJourney November 15, 2011 at 2:19 pm

Wow this finally cleared up the questions I’ve had about PCOS. Thank you!


normal menstrual cycle January 5, 2012 at 12:11 pm

Great information, makes it all clearer! Thank you very much for this. What a mess eh? We really need an instruction book to understand our own bodies. Quite unbelievable, so complex yet it all makes sense..


heather, RN June 23, 2012 at 3:54 pm

looking for a way to make it easier for my preteen daughter to understand how her period will differ from my period. as an RN, i love the way you have all this laid out. awesome graphics to show the difference between the “normal” cycle and the “PCOS” cycle. the best i’ve ever seen in terms of explaining the WHY behind our hormone imbalance. as a fellow “cyster”, i congratulate you on a job well done bringing this info to others! great job!!!


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