progesterone

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Benjamin Clanner-Engelshofen is a freelance writer in the medical department. He studied biochemistry and pharmacy in Munich and Cambridge / Boston (USA) and noticed early on that he particularly enjoyed the interface between medicine and science. That is why he went on to study human medicine.

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Progesterone is a naturally occurring sex hormone from the progestogen group. Above all, it regulates processes such as the menstrual cycle, pregnancy and the development of the embryo in the woman's body. As a drug, progesterone is usually administered when there is a hormone deficiency. Here you can read everything you need to know about progesterone - effect, use and side effects.

This is how progesterone works

Progesterone is a natural progestin (corpus luteum hormone) and is increasingly released in women in the second half of the menstrual cycle (also known as the secretion or luteal phase) from the corpus luteum. The corpus luteum is formed from the follicle in the ovary after the ovary has released a fertile egg cell into the fallopian tube (ovulation).

After the egg cell has been fertilized and implanted in the uterine lining, the progesterone level rises even further because the placenta continues to produce the hormone in order to calm the uterine muscles to protect the pregnancy.

Men also produce progesterone, albeit in very small quantities. Much less is known about its functions in the male body than about its importance in the female organism.

Normal values ​​of progesterone

Adult menstruating women have progesterone levels from almost 0 to an average of 13 nanograms per milliliter of blood, with fluctuations of up to a third being common. After menopause, when taking the contraceptive pill and in men, the normal progesterone values ​​are below one nanogram per milliliter.

Progesterone & Pregnancy

Progesterone is also known as the pregnancy hormone. In the second half of the menstrual cycle, it prepares the lining of the uterus (endometrium) for the possible implantation of a fertilized egg. If fertilization does not occur, the corpus luteum dissolves after about ten days. As a result, the progesterone concentration in the blood drops again and menstruation occurs.

Experts are discussing other effects of progesterone. During the implantation of the fertilized egg, the hormone seems to regulate the mother's immune system downwards so that it does not work against the implantation.

During pregnancy, progesterone is also supposed to inhibit the premature milk production in the breasts, so that the milk is only available for the baby after the birth. In addition, it is assumed that the drop in the progesterone level shortly before birth leads to the onset of the birth process and stimulates the uterine muscle activity, i.e. initiates labor.

In addition, the hormone is said to have other effects in the body, for example in the development of the central nervous system and in terms of memory.

Progesterone as a drug

In medicine, either orally ingested progesterone capsules are used or the active ingredient is administered locally (e.g. as a cream), parenterally (as an infusion) or vaginally.

After ingestion, the hormone is quickly and completely absorbed by the body, but 90 percent of it is immediately broken down in the liver. Therefore, the amount that gets into the bloodstream is only about a tenth of that ingested. The maximum blood values ​​are reached three to four hours after ingestion, but the values ​​quickly drop again.

With regular, twice daily intake, stable increased hormone concentrations in the body can be achieved.

When is progesterone used?

The administration of progesterone usually serves to compensate for a deficiency in the body's own hormone. For example, the active ingredient is used to support the luteal phase in the context of assisted reproduction (artificial insemination) and for hormone-related chest pain before the period (mastodynia).

The hormone is also used (often together with an estrogen) for menopausal symptoms (menopausal syndrome) that occur naturally or after the uterus has been surgically removed.

Use during pregnancy is limited in time. The use in menopause syndrome or hormone-related chest pain can also be used for a longer period of time.

This is how progesterone is used

The active ingredient can be taken as a soft capsule or applied locally as a progesterone cream, gel or vaginal tablet. Because the active ingredient is broken down very quickly in the body, it is usually used twice a day.

What are the side effects of progesterone?

Corresponding hormone preparations contain natural progesterone ("bioidentical progesterone") and are therefore usually well tolerated. Common progesterone side effects include fatigue, drowsiness, dizziness, headache and depressed mood. They occur in every tenth to one hundredth patient.

When the hormone is used locally (for example in the form of progesterone cream), side effects are much less common. Rashes and itching are most commonly seen. Headaches and tiredness are less common.

What should be considered when using progesterone?

Contraindications

Progesterone must not be used in:

• unexplained vaginal bleeding
• Tumor of the mammary gland or genital organs
• Porphyria (impaired breakdown of the red blood pigment)
• severe liver dysfunction

Interactions

Since externally supplied progesterone interferes with the female hormonal balance, the preparations should be used exactly as directed by a doctor.

The hormone is metabolized in the liver by enzymes (cytochrome P450 enzymes), which are also involved in the breakdown of many other drugs. These include active ingredients against epilepsy (phenobarbital, phenytoin, carbamazepine), the antibiotic rifampicin, the HIV drugs nevirapine and efavirenz, and St. John's wort (herbal antidepressant). If such drugs are taken at the same time, progesterone can therefore be broken down to a greater extent, which weakens its effect or even completely inhibits it.

Children and adolescents

Children should not use the hormone because of possible developmental disorders. Progesterone has no relevant use in children and adolescents, which is why it is extremely rarely used in this age group.

pregnancy and breast feeding period

Progesterone can be used during pregnancy: there is no increased risk of malformations. It has also been shown that vaginal use of progesterone reduces the risk of premature births in high-risk pregnancies.

There is no indication for the use of progesterone during breastfeeding. When used vaginally, studies have not observed any consequences in breastfed children.

How to get drugs with progesterone

In Germany, Austria and Switzerland, all dosage forms require a prescription, i.e. only available in pharmacies after a doctor's prescription.

Since when has progesterone been known?

Natural progesterone was discovered as early as 1934/35, with four different research groups publishing the discovery almost simultaneously. The hormone got its name from the group around Williard M. Allen, who derived it from "progestational steroidal ketone". This technical term describes the physiological effect, the general structure and a certain chemical characteristic of progesterone.

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