Amenorrhea (pronounced ah-men-o-REE-ah) is the absence of menstruation, which can be defined as missing one or more menstrual periods. It can be separated into primary and secondary amenorrhea, depending on whether a person experienced their first menstruation.
This article is pending medical review.
Written by Lea Dörner
Reviewed by Sophie Oppelt, Carolin Becker and Marjan Naghdi
Edited by Juliëtte Gossens
What we're covering
What is amenorrhea?
Amenorrhea is the absence of menstruation, which means you’ve missed one or more menstrual periods. It can be categorized as primary or secondary, which we'll explain below (1, 2).
After puberty, a person with female reproductive organs (ovaries and a uterus) goes through a sequence of monthly changes, known as the menstrual cycle. For more detailed information, we have an article dedicated to the menstrual cycle that you can find here.
Each person's cycle is unique, and the length varies from individual to individual. On average, a normal cycle lasts between 21 and 35 days (3). It's important to keep track of your menstrual patterns, because your menstrual cycle can tell you something about your overall health and well-being. Depending on your personal preference, apps or calendars can help you with that (1).
Now let's explore primary and secondary amenorrhea.
Primary amenorrhea is the absence of menstruation if you have not yet experienced your first menstruation, the menarche. In a person of the female biological sex, menarche is a late sign of puberty. It usually happens after the development of secondary sex characteristics. For most girls and teens with a female reproductive system, those characteristics are breasts, axillary hair, pubic hair, and a normal growth pattern (growing taller) (4).
Primary amenorrhea applies to teens aged 15 years or older who have already developed secondary sexual characteristics but haven't menstruated yet. The term also applies to those aged 13 or older who haven’t developed any secondary sex characteristics yet (4).
Secondary amenorrhea occurs when you experience the absence of menses (menstruation), after having gone through menarche. To be specific, it’s when there is an absence of menstruation after you have had three months of regular menstruation. It also applies when you’re not menstruating after you’ve had six months of irregular menstruation.
The absence of menstruation can have many different causes, depending on the person's age and sexual activity.
The most common causes of secondary amenorrhea are physiological – meaning they’re a normal and healthy consequence of what’s happening in your body at that moment. This includes pregnancy, menopause, and lactation, meaning the production of breastmilk. In fact, lactational amenorrhea is sometimes used as a form of birth control.
When these causes are excluded, most of the causes for primary and secondary amenorrhea are the same. Only when those physiological causes have been excluded, can we speak of a condition that might indicate a disease (1, 2, 5).
The following are some possible causes for the absence of your menstruation. But remember that it’s always best to discuss your specific case with your doctor!
Causes of amenorrhea
To identify potential causes of primary and secondary amenorrhea, it’s important to understand the hormonal systems (endocrine systems) that control puberty and the menstrual cycle.
Specifically, the hypothalamic-pituitary-gonadal (HPG) axis (system) plays a crucial role (6). This system connects the hypothalamus and the pituitary gland in the brain to the gonads (the ovaries and testicles). With the onset of puberty, the axis is activated and releases hormones that regulate the menstrual cycle (7, 8). Disruptions to the HPG axis commonly cause amenorrhea (4, 9).
Stress, Nutritional Deficiency, and Inflammation
Both primary and secondary amenorrhea can be caused by stress, weight loss or low body fat, or excessive exercise. As a result, eating disorders (such as anorexia or bulimia) often lead to the absence of menstruation. Other chronic diseases and inflammation (for example, diabetes) can also lead to amenorrhea.
These factors suppress the HPG axis and prevent ovulation. This type of amenorrhea is called functional hypothalamic amenorrhea (FHA). FHA is commonly seen in adolescents. It’s thought to be the body's adaptive response to a lack of energy or to inflammation (10).
Endocrine (Hormonal) Disorders
Primary and secondary amenorrhea can develop due to issues within the complicated hormonal system. These can include problems with hormone release in the HPG axis, or disorders of other endocrine (hormone-producing) glands such as the ovaries (for example, if you have PCOS or a thyroid problem). If the uterus is not working well, so that it that prevents proper response to these hormones, this can also cause the absence of menstruation. (1, 4)
Anatomical Abnormalities of the Reproductive Tract
A common cause of primary amenorrhea is anatomical abnormalities in the reproductive tract. These anatomical changes are genetic, and there are different possibilities as to which parts of the reproductive tract are affected.
An imperforate hymen, for example, is a condition where the hymen covers the entire vaginal opening, closing it. The hymen is a membrane that normally only surrounds the vaginal opening (2).
Another example of such a condition is Müllerian aplasia. In this disorder, the müllerian ducts don’t develop well when you’re still an embryo. These ducts normally develop into female reproductive organs. The underdevelopment can result in the absence or failed development of the vagina, uterus, or both. (11, 12)
Drugs and Medication
There are various medications that can be responsible for the absence of menstruation. For example, amenorrhea is a common side effect of antipsychotic and anti-epileptic drugs.
Opioids and alcohol can also be a cause, because long-term use affects the HPG axis. (13)
Tumors and Cysts
Finally, tumors or cysts are a rare cause of both primary and secondary amenorrhea. Cysts are sacs filled with fluid, like a water-filled balloon. These can affect either the hormonal glands or organs of the reproductive tract. Possible structures that can lead to this include ovarian cysts and tumors, or fibroids (growths) in the uterus. (4)
Evaluation and diagnosis
As you can see from the list of possible causes of amenorrhea, there are numerous reasons why menstruation may be absent. That’s why your doctor will have to ask you a range of questions, and maybe do a physical examination.
Your doctor will likely begin by asking about:
Your past menstrual patterns, including regularity, duration and flow of your period
Medications you're using
Your general health history, including chronic illnesses or pre-existing conditions of family members
Additionally, they will likely want to rule out pregnancy by having you take a pregnancy test.
If your doctor suspects functional hypothalamic amenorrhea (FHA), they may also ask about any stress you’ve been having, your exercise and eating habits, and your weight, height, and BMI (body mass index).
During physical examination, your doctor will probably want to examine the anatomy and development of your sexual organs. An external examination, with ultrasound of your belly, is usually sufficient to evaluate your internal reproductive organs.
Finally, an evaluation of hormone levels is typically part of the examination, which can be done via blood samples. (1, 2, 4)
Treatment of amenorrhea
Treatment options for amenorrhea often vary depending on the cause. Some causes can be treated or resolved through methods such as minor surgery for an imperforate hymen. Others may be addressed through lifestyle changes, such as changing your eating or exercise habits and stress management techniques (14). Sometimes, it’s a good idea to get therapy to work through any psychological issues that are giving you stress. Hormone therapy might also be an option for cases where there is an imbalance in hormone levels.
Your doctor will evaluate the cause of your amenorrhea and suggest the best course of treatment for you. Of course, if the cause of your amenorrhea is physiological (normal), then it doesn't need treatment. For example, if you stop breastfeeding, your menstruation will eventually return on its own.
In summary, there are many different reasons for why you’re not menstruating. Accordingly, there are many different treatment options. In any case, you should contact your doctor if you experience amenorrhea, to clarify what is going on in your specific case.
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