Preconception 101

Lesson 1: Hormones 101

1. Pre-Ovulatory Hormones - Discussing Estrogen, FSH, LH and GnRH 2. Post-Ovulatory Hormones - Discussing Progesterone, hCG and Prolactin 3. Dispelling Day 14 Myth - Detailing the mechanics of ovulation.

Pre-Ovulatory Hormones – Estrogen, FSH, GnRH, LH

The female reproductive cycle is completely run by hormones. Without the hormones, conception would not occur. It’s no wonder that if any of the key hormones are out of whack then infertility is the result. Maintaining a balance of this fine tuned system of glands and hormone excretions is paramount in the act of conception. It has been said that hormones are the conductor of the body during pregnancy, that hormones run the show, so to speak. Learning about the reproductive hormones can give you a better understanding of what occurs during the cycle month and why you experience certain physical signs as each hormone peaks and drops off in production. These reproductive hormones are released mainly in the pre-ovulatory phase of the cycle, or the first half.

Estrogen

Estrogen is actually a term referring to three separate hormones – estrone, estradiol, and estriol. Because these three hormones are considered the “estrus-producing hormones” it is easier to simply say “estrogen” which refers to the “estrus” class of hormones.

Estrogen is the hormone responsible for the low basal body temperatures in the first half of the cycle. Estrogen prompts the cervix to produce the fertile quality cervical fluid. It controls the entire menstrual cycle. Estrogen levels start off low the first of the cycle and begin to climb as ovulation approaches. It’s the high levels of estrogen that prompt the production of the Luteinizing Hormone (LH).

Luteinizing Hormone (LH)

LH is produced by the pituitary gland. It is released in one surge prior to ovulation, which in fact prompts ovulation to occur. LH levels rise very slowly at the first half of the cycle. When the level of estrogen reaches a high peak it prompts the surge release of LH, known as the LH surge. It’s the LH surge that literally causes the ovary to burst forth the egg.

LH is the hormone detected in ovulation predictor kits. This surge takes place normally 24 hours to 72 hours before ovulation occurs. If infertility is a factor, a woman can have several LH surges in a cycle, thus making the use of ovulation predictor kits more complicated.

Follicle-Stimulating Hormone (FSH)

FSH is produced by the pituitary gland in the first half of the reproductive cycle. FSH is the hormone responsible for prompting the ovaries to produce mature ova or eggs – and the production of estrogen. The levels of FSH are above those of the other reproductive hormones at the beginning of the cycle. Very soon, the levels drop below the levels of the other reproductive hormones. Right before ovulation, FSH peaks, thus causing ovulation itself to happen.

Gonadotropin Releasing Hormone (GnRH)

GnRH is produced by the hypothalamus in the brain. It stimulates the pituitary gland in the production of FSH and lutenizing hormone (LH). This helps in the lead to follicle development and ovulation.

The hormones that run the pre-ovulatory phase of the menstrual cycle are estrogen (estrone, estradiol, and estriol), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and gonadotropin releasing hormone (GnRH). These hormones must work in harmony to bring about ovulation, the release of the egg from the ovary.

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