Known as one of the female hormones, the progesterone hormone is famous for playing important roles in pregnancy as well as in menstrual cycles and fertility. Even the word progesterone is derived from the concept of “promoting gestation.”
Progesterone functions primarily in the menstrual cycle that continues every month. When the ovulation phase begins in the middle of the cycle, an egg is released from the ovaries. If this egg is fertilized, it will move into the uterus and attach to the uterine wall. At this point, the progesterone hormone steps in and works to make the uterine wall so that the fertilized egg, the embryo, can easily hold and be fed. The intrauterine walls and tissues, which thicken thanks to the progesterone hormone, develop enough to feed the embryo.
If a fertilized egg does not attach to the uterine wall, that is, pregnancy does not occur, the rate of progesterone secreted in the body begins to decrease and the preparation for pregnancy in the uterus is thrown out; Menstrual bleeding is seen in about 2 weeks. If the egg is fertilized and moves towards and clings to the uterine wall, progesterone continues to be produced in the ovaries for about eight weeks, and in this way, the uterus develops so that the embryo can easily grow here, preparing a place for the fetus. When the first eight weeks of pregnancy are completed, progesterone secretion continues thanks to the placenta formed with the baby.
The progesterone hormone plays an important role in the formation of pregnancy as well as in the continuation of pregnancy. Progesterone rate secreted in the ovaries begins to decrease in the advanced ages (in the perimenopause phase) when fertility starts to decrease in women. During the menopause process, the amount of progesterone in the body has decreased as much as it is seen in the male body. Research in recent years has revealed that progesterone is linked not only to fertility and pregnancy, but also to many important functions in the body. It is especially noteworthy that progesterone affects breast health, cardiovascular health and nervous system as well as brain functions.
Because of its critical functions in the nervous system, progesterone hormone has been accepted among the “neurosteroids”. All cells in the brain, spinal cord, and peripheral nervous system synthesize the progesterone hormone from cholesterol. Progesterone in the bloodstream also has direct access to the brain and nerves. Progesterone is required for normal brain functions in the nervous system, and one of the important roles of this hormone is that it also promotes post-injury repair by protecting the brain from damage. By promoting the growth and repair of the myelin sheath that protects nerve fibers, progesterone perfectly supports the self-renewal and healing ability of the brain and can protect it from brain damage even after traumatic injuries.
In studies conducted over 20 years ago, scientists studied mice that received brain damage. Female rats in their cycle when progesterone levels were highest had significantly less brain damage than male rats and other female rats with lower progesterone levels. This and similar studies have also paved the way for clinical studies showing that natural progesterone secreted in high doses protects against traumatic brain damage.
In another study called “ProTECT”, intensive care patients with acute traumatic brain injury were administered high doses of progesterone for 3 days. The mortality rate for patients treated with progesterone was found to be 13%, while the mortality rate was 30% in patients treated with placebo. Another review reveals that progesterone may play an important role not only in treating traumatic brain injury, but also in the treatment of stroke due to its powerful protective effects on brain tissue. Researchers agree that natural progesterone is a safety alternative with no long-term side effects.
There is evidence that babies of women treated with progesterone supplements during pregnancy show better brain development, have better academic results at ages 9-10, and are significantly more likely to have college education. It is thought that the progesterone levels being below normal during pregnancy will negatively affect the brain development of the baby.
It is also known that the positive effect of progesterone hormone on brain tissues creates a natural calming effect. Progesterone, which is also effective in reducing anxiety symptoms and strengthening memory, can cause a decline in cognitive functions when it begins to decrease with age. The soothing effects can be noticed in women who use progesterone supplements, and the reason why the oral form is generally recommended before bedtime is that progesterone supports sleep state, especially in women who suffer from insomnia during the premenopausal period.
Synthetically produced progestins that can be recommended as progesterone supplements are molecularly different from the natural progesterone hormone and therefore may not function in the same way in metabolism and bind to the same compounds. Therefore, progestins do not show any of the neuroprotective (protective-neurological) effects. Moreover, MPA (medroxyprogesterone acetate) used in synthetic hormone replacement therapy has been found to have adverse effects on the nervous system and reduce the beneficial effects of the estrogen hormone as well.
Referans: Margaret N. Groves. “Progesterone and the Nervous System/Brain”. Şuradan alındı: https://womeninbalance.org/resources-research/progesterone-and-the-nervous-systembrain/.