Progesterone - far more than just a pregnancy hormone

Progesterone is a remarkable hormone that some women unfortunately have too little of. Low progesterone levels can cause unpleasant symptoms and have a negative impact on health and fertility. This article summarizes what you should know about low progesterone levels and how you can increase your progesterone naturally.

What exactly is progesterone?

Progesterone, also known as the luteal hormone, plays a prominent role in the second half of the menstrual cycle. It transforms the lining of the uterus, which has been prepared by oestrogen, so that it is ideally suited for the implantation of a fertilized egg. Progesterone supports the growth of the uterus and prepares the mammary glands for breastfeeding. If pregnancy does not occur during this cycle, the progesterone level drops dramatically at the end of the second half of the cycle and the next menstruation begins.

Progesterone is therefore crucial for a stable menstrual cycle. A deficiency of this hormone inevitably leads to cycle disorders. Similar to oestrogens, progesterone also has a variety of effects on other organ systems such as bones, intestines and blood vessels. Progesterone has a particular effect on the brain, where it has a calming, sometimes even slightly tiring effect. This also explains why many women complain of tiredness during pregnancy, when progesterone levels are particularly high. Progesterone also influences the smooth muscles by reducing the tension of the smooth muscle fibers. This explains why varicose veins are particularly common during pregnancy. Progesterone is only produced in significant quantities in the ovaries and during pregnancy in the placenta.

What does progesterone deficiency mean?

Progesterone deficiency, also known as corpus luteum insufficiency (CLI), is a common cause of infertility in women. This condition is caused by insufficient production of the corpus luteum hormone (progesterone). This hormone is produced in the ovaries by the corpus luteum (yellow body) after ovulation and plays a crucial role in preparing the uterus for the implantation of a fertilized egg and a possible pregnancy.

How do I recognize a progesterone deficiency?

Luteal insufficiency can occur subtly and is often not easy to recognize. For example, a shortened cycle, especially in the second half of the cycle, i.e. after ovulation, can be an indication. Women who use a Daysy can also monitor their temperature curve after ovulation in the DaysyDay app. Normally, a characteristic temperature elevationshould be recognizable. If this phase lasts less than ten days, the basal body temperature rises only very slowly or remains at a low level, this could indicate a weakness of the corpus luteum.

It is important to know that it can always happen that the temperature curve does not rise clearly or the cycle is sometimes a little shorter, but this is absolutely no cause for concern. However, if you notice that the BBT is frequently very low in the second half of the cycle, or the luteal phase is significantly shorter after ovulation, you are welcome to contact our customer service ( and we can take a look at your data together.

What effects can a progesterone deficiency have?

The effects of luteal insufficiency are particularly important for women who want to have children. A lack of progesterone can result in the fertilized egg not being able to implant properly in the uterus. This can lead to either a lack of pregnancy or an increased risk of miscarriage in the first twelve weeks of pregnancy. After the 12th week, the placenta takes over the production of progesterone.

Women who do not wish to have children can suffer more from premenstrual syndrome (PMS) and spotting before the actual period, due to a progesterone deficiency. Here too, it is important to note that there may be other causes behind these symptoms.

What are the possible causes of a progesterone deficiency?

The causes of progesterone deficiency can be varied. During puberty and menopause, a certain lack of progesterone is normal. At childbearing age, the deficiency can be of organic origin, for example due to autoimmune diseases or disorders in the pituitary gland that affect hormone production.

Physical or emotional stress can also lead to luteal insufficiency. If a deficiency is suspected or you are having difficulty getting pregnant, it is always advisable to consult a doctor and have a blood test within the luteal phase to check your progesterone levels.

How is a progesterone deficiency diagnosed?

The exact diagnosis of luteal insufficiency requires a comprehensive examination and laboratory tests. Blood is usually taken during the luteal phase to measure progesterone levels. 

What are the treatment options for progesterone deficiency?

The treatment of luteal insufficiency depends on the cause and the woman's desire to have children. If progesterone deficiency is proven, progesterone can be administered in the form of vaginal suppositories or oral medication during the luteal phase to increase progesterone levels and support implantation.

For some women, lifestyle changes can help to improve hormone balance. Stress management, a balanced diet, and regular exercise can have a positive impact on hormone levels.

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Author: Dr. Niels van de Roemer