Progesterone

After ovulation, which is triggered by a rapid increase in LH, the so-called “LH peak”, the corpus luteum produces progesterone. The corpus luteum is formed from the ovarian follicle after ovulation. In non-pregnant women, unlike estrogens, progesterone is produced exclusively in the ovaries.

During pregnancy, progesterone is produced in much higher quantities by the placenta. Like the estrogens, progesterone is able to penetrate into the cells and mediate its action via receptors located inside the cells. In the case of progesterone receptors, a distinction is also made between the receptor types PR-A and PR-B.

The following effects are mediated via the progesterone receptor PR-B: Even before the last menstrual bleeding (menopause), progesterone production decreases in the second half of the cycle (luteal phase) until it finally stops. The drop in progesterone levels results in a reduced ability to conceive (conception ability), i.e. the probability of achieving pregnancy is reduced by the low progesterone level. Cycle disorders with irregular bleeding can also be explained by the reduced progesterone level.

If this is to be determined in the blood, the blood sample must be taken in the second half of the cycle.The reduced progesterone level, just like the estrogen deficiency, can cause menopausal symptoms such as irritability or sleep disorders. The following values are regarded as normal for progesterone: In the first trimester of pregnancy values between 10 and 50 ng/ml are found, in the second trimester the progesterone level is usually between 20 and 130 ng/ml and in the last trimester it rises to 130-260 ng/ml.

Maintenance of a pregnancy by preventing menstruation and relaxing the muscular layer of the uterus (myometrium)
The secretory transformation of the uterine lining (endometrium) in the second half of the female cycle
An increase in body temperature of about 0.5 °C also in the second half of the cycle
Finally, progesterone also inhibits the formation of estrogen receptors, so progesterone limits the effect of estradiol.
Puberty 0-2 ng/ml
Follicular phase < 1 ng/ml
Luteal phase > 12 ng/ml
And in postmenopause < 1 ng/ml