Your period doesn't come: there can be many causes

It is not quite as precise as Swiss clockwork, but it is a reliable companion in a woman's life for many years: menstruation. This makes it all the more worrying when it suddenly stops for seemingly no reason. "Am I pregnant?" is usually the first thought. In fact, this is of course the most common cause of a missed period, medically known as "amenorrhoea". However, other major hormonal upheavals in a woman's life, such as breastfeeding or the years before the menopause (last menstrual period), can also cause menstruation to stop.

But what if pregnancy can be ruled out and the menopause is still a long way off? What are the possible reasons why the uterine lining is neither built up nor shed?

Almost every menstruating person is familiar with the fact that menstruation is sometimes delayed. This is because the cycle is sometimes out of sync, which is based on a delicate hormonal balance: The hormones have to be produced in the body in exactly the right order so that the uterus is prepared for a possible pregnancy and - if this does not occur - the subsequent breakdown of the built-up mucous membrane ends in menstruation. And so, in addition to the usual cycle length of 28 days, cycle lengths of between 25 and 35 days are also considered normal.

Not pregnant: other reasons why your period may not come

Primary amenorrhoea is when a girl has not had her first period by the age of 15. Secondary amenorrhoea, on the other hand, affects women who already had a regular menstrual cycle and suddenly, without pregnancy, report missing periods. The following rule of thumb applies: a doctor will only diagnose secondary amenorrhoea if the absence is more than three months (for women with an irregular cycle: more than six months). According to specialist literature, this form of amenorrhoea occurs in two to five per cent of women of childbearing age.

PCOS or disorder in the hypothalamus

The most common cause of this is polycystic ovary syndrome (PCOS), which you can find out more about in this article. However, there may also be a disruption of the hormonal control centre in the brain: Normally, the hypothalamus releases GnRH (gonadotropin-releasing hormone) every 90 minutes, which stimulates the ovaries. Functional hypothalamic amenorrhoea, or ovulatory dysfunction in medical terminology, is, according to of this study, it is responsible for around a third of cases of secondary amenorrhoea and can have the following causes, often in combination:

• psychosocial stress
• Competitive sport
• Weight loss (often due to anorexia or bulimia)

However, even dieting is capable of upsetting the balanced interplay of hormones. "In order for the clock in the hypothalamus to function and regularly release GnRH, the body needs a minimum fat mass of 22 per cent. the body mass index must be >19", according to the website of "Frauenärzte im Netz". Psychosocial stress, in turn, releases more of the hormones that reduce the release of GnRH in the hypothalamus.

Medication, thyroid, infection, prolactinoma:

In addition, taking medication may also cause your period to stop. These include:

• Hormonal contraceptives (birth control pill)
• Glucocorticoids (cortisone preparations)
• Certain psychotropic drugs
• Anti-hormone preparations in the course of cancer therapy or cancer medication after chemotherapy

Damage to the lining of the uterus is also held responsible for secondary amenorrhoea - for example, if a curettage has been performed or an infection is present. Alternatively, the thyroid gland, as the body's hormonal clock, interferes with menstruation and changes it in the event of hyperthyroidism or hypothyroidism (such as Hashimoto or causes it to stop altogether. And even if hyperprolactinaemia, i.e. an excess of the milk-forming hormone prolactin in the blood, usually indicates pregnancy, it can also be caused by a benign pituitary tumour, a prolactinoma.

As you can see, there are a number of causes for a missed period. Please consult a doctor for clarification. And don't hesitate to do so earlier than the medical rule of thumb advises. <p