hormones and menstrual cycle

Hormones and menstrual cycle

July 03, 2017 - by Ava Rose - in PCOS Causes

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FSH, LH, Estrogen, Progesterone are 4 main players in regulating the menstrual cycle. Two of them are from the pituitary glands (Gonadotropins) and the other two are from the ovaries (Ovarian or sex hormones).

  • FSH (Follicle Stimulating hormone) to mature the follicles.
  • LH (Luteinizing hormone) that causes the ovulation.
  • Estrogen that controls the LH surge by a feedback regulation mechanism. It also prepares the uterus by thickening the lining.
  • 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

The following is the sequence of events during the normal menstrual cycle.

  1. Hypothalamus releases Gonadotropin-releasing hormone (GnRH)
  2. GnRH causes the pituitary gland to produce FSH. FSH reaches the ovaries via the blood stream. FSH causes the follicles to mature. Follicles are little balloon like sacs filled with cells and fluid and hold an egg. Each follicle contains one single egg.
  3. Maturing follicles produce estrogen. Estrogen signals the brain, which slows down the FSH production and starts LH production in pituitary glands.
  4. Estrogen also prepares the uterus for ovulation by thickening the blood vessels lining the uterus.
  5. Estrogen production boosts LH.
  6. LH surges and causes ovulation. The egg escapes, travels via the fallopian tube and goes to the Uterus.
  7. The empty follicle from which the egg was released is called as Corpus Luteum or yellow body. The Corpus Luteum produces Progesterone. Progesterone signals the brain to stop producing LH.
  8. Progesterone also prepares the uterus by thickening the uterus lining and also producing mucus to ease the passage of the sperm. The egg sits and waits for 24-48 hrs.
  9. If you get pregnant, the hCG hormone is produced by the developing embryo. This hormone signals the Corpus Luteum to keep making Progesterone and Estrogen. If you don’t get pregnant, the corpus luteum disintegrates (called as Corpus Albican) and stops producing Progesterone and Estrogen. The low levels of Progesterone and Estrogen causes menstruation to occur.
  10. The cycle starts all over again.

Hormones in abnormal menstrual cycle with PCOS

What happens to these hormones with PCOS? Basically they are go haywire. 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.

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 that is responsible for hiding the beauty underneath all the acne, hair growth and the weight gain that just won’t come off.

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