Hormones of the Reproductive Cycle

The Basics

Hormones are chemicals produced in the body that circulate through blood. Each hormone has a different role to play, especially within the reproductive cycle. The ultimate goal of these reproductive hormones is to support the process of ovulation and EITHER implantation and pregnancy OR the resetting of the uterus that happens when implantation does not occur.

For females, there are five main hormones working together at very specific times to do very specific things-take one away or have too much of another and the whole system goes out of whack. The flow chart below helps us see where each hormone is active in the body.

Gonadotropin-releasing hormone

Also known as GnRH
Made by the hypothalamus in the brain
Causes the release of FSH & LH

Follicle-Stimulating Hormone

Also known as FSH
Produced by the pituitary gland in the brain
Helps control the production and maturing of the egg

Luteinizing Hormone

Also known as LH
Produced in pituitary gland in the brain
Triggers ovulation
Signals ovaries to make estrogen and progesterone

Estrogen

Produced by ovaries when not pregnant
Produced by the placenta during pregnancy
Helps the egg mature and move from the ovary to the uterus

Progesterone

Produced by the corpus luteum in an ovary
Preps the lining of the uterus to receive the egg
Suppresses estrogen after ovulation
Supports healthy pregnancy

In addition to those explored above, testosterone and hCG also affect the reproductive cycle. Testosterone regulates sex drive while hCG keeps the progesterone flowing if implantation of the egg happens. This is the hormone detected when you take a home pregnancy test!

Real-Time Changes

WEEK 1: This is the start of your period to the end and maybe a day or two beyond. Estrogen is low to begin with and then rises slowly over the week. You might feel fatigued and achy, uninterested in sex, and starving during the first part of the week. You'll slowly shift to gain energy and feel more up for activities across the board.

WEEK 2: This is the end of your period to ovulation. FSH, LH, estrogen and testosterone rise, improving your mood and energy as well as your libido. Your eggs are working hard to mature and be released into the uterus.

WEEK 3: This is when ovulation ends and implantation can occur. Progesterone is on the rise, which means estrogen dips. Mood can begin to shift and you may have more cravings. If fertilization and implantation don't occur, the egg will begin to deteriorate quickly.

WEEK 4: Estrogen and progesterone drop as you move toward your period. You may get really irritable and need more sleep. This is when PMS symptoms arise if you experience them.