3 min|Rhiannon Lockhart

Get To Know Your Hormones: Progesterone

Hormones

Our body does a lot behind the scenes.

One perfect example of this is the many jobs played out by our hormones. In this article, we’ll review progesterone and its effects through puberty to menopause.

A little about progesterone

Progesterone is produced by the adrenal cortex (the outer part of your adrenal gland), as well as the ovaries in females and the testes in males. In the first weeks of pregnancy, it is also secreted by the corpus luteum (a temporary endocrine structure existing during the luteal phase), then the placenta. (1) (2)

Progesterone is made from its precursor hormone, pregnenolone. Fun fact: pregnenolone is derived from cholesterol and is needed to make most steroid hormones.

What does progesterone do?

Depending on your stage of life, progesterone will play different roles. One of its major roles takes place in pregnancy, so let’s start there!

Progesterone in pregnancy:

After we ovulate, progesterone increases to prepare the endometrium for a possible pregnancy – thickening the lining and restricting muscle contractions that would release the egg. Without a pregnancy, the body experiences a period, but if conception is successful it also supports the nourishment of the growing fetus and prevents further ovulation. During this time, progesterone is secreted from the corpus luteum until the placenta is developed and takes over production. (3) Progesterone also helps to prepare the breasts for milk production and strengthen muscles in the pelvic wall.

Low progesterone levels are often associated with increased miscarriage and preterm delivery risk.

Progesterone in females of reproductive age (not pregnant):

Right before we ovulate, there is a surge in the luteinizing hormone (LH), which triggers the increase in progesterone near the end of the follicular phase (the first half of our cycle). Similarly to pregnancy, progesterone increases in anticipation of implantation and a pregnancy. In the case of no pregnancy, progesterone levels decrease triggering a bleed.

However, imbalanced progesterone levels can lead to a host of issues for menstruating people in and out of pregnancy. We’ll dive into the symptoms of low progesterone shortly.

Progesterone through menopause:

Simply put, progesterone and estrogen both decline in menopause, resulting in some of the common symptoms like hot flashes, weight gain, night sweats, insomnia or mood swings and low libido.

What does progesterone do in males?

Progesterone has many roles in males, especially around sperm health as it influences spermatogenesis (the production of sperm), how it can fertilize an egg, testosterone biosynthesis, as well as supporting sleep, the immune system, cardiovascular system, kidney function, adipose tissue and behaviour. (4)

About low progesterone

Progesterone is important for many functions, and in females, dysregulated progesterone levels typically appear through symptoms related to the menstrual cycle.

Symptoms of low progesterone (5):

Irregular or absent periods
Difficulty conceiving
Hormonal headaches
Mood changes
Recurrent miscarriage
Decreased libido
Spotting or abdominal pain in pregnancy
An imbalance of estrogen to progesterone

What can cause low progesterone (5):

Age. As females get older and enter into menopause, we have naturally lower levels of progesterone
Polycystic ovarian syndrome (PCOS)
Increased stress and cortisol
Hypothyroidism or an underactive thyroid
Hyperprolactinemia
Low cholesterol
Caloric restriction and over-exercising