Menstrual bleeding is a sign of a periodic process controlled by many hormones. Disturbances in the regulatory structure can lead to deviations in the strength, duration and regularity of the period. Sometimes it does not occur at all. Read here about the causes behind a missed period and what you can do about it.
Primary and secondary amenorrhea
The female menstrual cycle occurs at regular intervals on average between the ages of 13 and 45 and lasts 25-35 days. Its purpose is to make an egg available for reproduction. If fertilization does not occur after ovulation, the top layer of the uterine lining is shed and menstrual bleeding begins, lasting about 3-7 days. The first day of bleeding corresponds to the beginning of the new cycle.
This process always follows the same pattern and is controlled by various sex hormones, mainly from the brain (FSH, LH) and ovaries (estrogen, progesterone). Menstrual disorders can have psychological or physical causes.
- Primary amenorrhea: no menstrual period occurs until the age of 18.
- Secondary amenorrhea: There was already a normal cycle, then the bleeding is absent for at least 3 months.
Causes of amenorrhea
In the primary form, there are almost always underlying physical causes. These include congenital chromosomal abnormalities and genital malformations, ovarian dysfunction and hormonal disorders mainly in the diencephalon and pituitary gland.
In the secondary form, it is not uncommon for phases of psychological or physical stress to be the cause. This includes, for example, (work-related) stress, travel, upcoming important decisions or family events. What happens in detail on the hormonal level is not yet fully understood. However, it is assumed that such situations can trigger malfunctions in the nervous system that affect hormone regulation.
Especially in younger women, large weight fluctuations or severe weight loss, such as in anorexia, can lead to missed periods.
Hormone imbalances as a cause
Hormone imbalances and metabolic disorders affect women at any age. For example, elevated blood levels of male sex hormones lead to missed periods, an effect familiar to female athletes who take anabolic steroids to build muscle.
Rarer triggers are hormone-producing tumors in the ovary, severe general illnesses and medications, especially hormone preparations and cancer drugs, but also psychotropic drugs and tablets to lower blood pressure. After discontinuing the pill, it may take several weeks for the cycle to return to normal (“post-pill amenorrhea“).
In addition to pathological forms, there is also physiological, i.e. normal, amenorrhea, which is caused by hormonal changes during pregnancy and breastfeeding, as well as during and after menopause. Incidentally, even if menstruation stops for a few weeks after childbirth, there is no adequate protection against becoming pregnant again, at least if the woman is not breastfeeding.
