What is Amenorrhea?

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Medically reviewed by Dr. Stacy Hengisman MD and Felice Ramallo MSRD.

Did you know there is a word for the absence of a menstrual period? The medical term is “amenorrhea,” and there are two types: primary and secondary. Primary amenorrhea is when you are aged 16 and older and haven’t got your first period, while secondary amenorrhea is typically diagnosed when you have had your period for 9 months or more, but you have a 3 month (or longer) gap in which you have stopped menstruating. Like many health issues, amenorrhea can be extremely distressing and confusing to be diagnosed with; fortunately, there is a set of criteria for diagnosing this condition, common causes that medical professionals can point to (and try to address), as well as treatment options on how you can get your period back, depending on the underlying cause for the condition. If you are struggling with amenorrhea, know you are not alone, as 1 in 25 women of reproductive age will struggle with this condition in their lifetime, according to the American College of Obstetricians and Gynecologists (ACOG). 

What is amenorrhea? 

A typical period

To best understand amenorrhea, let’s talk about what a regular menstrual cycle looks like. 

According to ACOG, “a menstrual cycle is counted from the first day of bleeding of one menstrual period to the first day of bleeding of the next period. Most women have a menstrual cycle that lasts between 21 and 35 days.” 

This means that if you get your period more than every 21 days, or less frequently than every 35 days, then your cycle is irregular. Of course, just because you skip your period one month, or you get your period a few days early, this does not automatically mean that your period is irregular. It’s important to look at the big picture when it comes to your period: do you frequently skip a month? Does your period come less often than every 35 days on a regular basis? To know the answers to these questions, many women find it helpful to use a free app that helps them track their period dates, in addition to physical and emotional symptoms. This is so they better know when to expect their period, if they are running late (which can easily happen without us realizing, if we don’t make a note of when our last period was!), and maybe most importantly: if something feels off. 

ACOG also notes that a typical period “lasts 2 to 7 days, with the heaviest bleeding in the first 3 days.” If your period lasts longer than 7 days, or is shorter than 2, this is unusual and you should make an appointment with your primary care physician. 

Why you should care about your period 

You should care about your period because it can be a useful signifier of your overall health

Your period can tell you a lot! For instance, sometimes if you are stressed, your menstrual cycle can get longer or shorter than normal. In other cases, if you are exercising too much, lose too much body fat, or lose too much weight in general (or all three), your period may stop since your body can’t produce the hormones needed to ovulate. This is your body trying to tell you that it isn’t getting enough of what it needs to function properly.   

Types of amenorrhea 

Like we mentioned earlier, amenorrhea describes “the absence of menstrual bleeding.” If you are aged 15 or older and haven’t got your period yet, or you have missed three periods in a row - it is critical that you make an appointment with your doctor to find out what may be going on, according to ACOG. 

That being said, let’s dig a little deeper into primary and secondary amenorrhea. 

Primary amenorrhea is when you haven’t had your period by the age of 15; according to the National Institute of Health, “the majority of cases of primary amenorrhea are caused by anatomical defects, elevated FSH levels, hyperprolactinemia, hypothalamic amenorrhea, or PCOS.” They add that gonadal dysgenesis (when the gonads do not develop properly) includes “most commonly” Turner syndrome, a condition in which one of the X chromosomes is partially or fully missing, and this comprises “up to 43% of primary amenorrhea cases.”  

Secondary amenorrhea is evaluated when 3 months have passed since your last period, without explanation, according to the ACOG. Of course, this does not mean you have to wait until 3 months have passed without a period to visit the doctor: in fact, if you feel something is off in your body, or your periods have suddenly stopped, it is extremely important that you make an appointment with a doctor as soon as possible to see what’s going on. There are three common causes of secondary amenorrhea: 1) a hormonal disturbance or imbalance which leads to a lack of ovulation, 2) physical damage to the endometrium, preventing its growth, or 3) a physical “obstruction of the outflow path of the menstrual blood.” We will talk more about the causes of primary and secondary amenorrhea in a moment. 

Diagnosing amenorrhea 

What to expect at a doctor’s appointment

A doctor will typically go about diagnosing amenorrhea by:


  • Conducting a series of physical exams and tests. 
  • This will likely include a urinary pregnancy test to make sure that this isn’t the cause behind your lack of menstruation. 
  • Asking you about your medical history and potentially inquiring about your family’s medical history for better context as to what could be going on.
  • Evaluating any symptoms (which we will list below), which may inform testing
  • Asking about past periods, such as the date of your last period, whether they have typically been irregular or regular, heavy, light, and other questions
  • This is why using a period tracking app can be extremely useful! There are plenty of free ones out there where you can simply log the date of your period, how long it lasted, and any symptoms. Over time, you may see a pattern emerge, or a lack of a pattern: all this data can be useful to raise with your doctor. 

Symptoms accompanying amenorrhea 

Though the main symptom of amenorrhea is the absence of a period, other symptoms that appear can contain clues that indicate the underlying cause behind your amenorrhea. Common physical symptoms can include: 

  • Hot flashes 
  • Nipples leaking milk
  • Vaginal dryness
  • Headaches
  • Vision changes 
  • Acne 
  • Excess hair growth on the face or body 

Using symptoms to understand underlying causes 

There are “natural” reasons to experience amenorrhea, such as by becoming pregnant, breastfeeding, menopause, or having surgery to remove your uterus or ovaries. 

If we look at the list of symptoms above, we see that hot flashes could indicate perimenopause, while nipples leaking milk is a common side effect of breastfeeding, and this could be insightful in guessing not only the cause behind the amenorrhea, but how long it will last, and what steps - if any - need to be taken to get one's period back. Like we mentioned earlier, though, these symptoms are not prescriptive; they can simply be helpful in exploring what rounds of testing to pursue first or what treatment plan to follow. For example, acne and excess hair growth as symptoms could indicate PCOS, in which case testing thyroid health, as well as androgen levels, could be a path for exploration for a patient and their doctor. 

 Causes of amenorrhea 

Here we’ve listed the most common reasons for both primary and secondary amenorrhea. You’ll see that, in some cases, amenorrhea is an expected (or even desired) outcome, like in the case of taking birth control to stop heavy and painful periods, while in other circumstances amenorrhea is undesired and difficult to resolve. 

Primary amenorrhea causes:

  • Chromosomal or genetic problems affecting your reproductive system, such as Turner syndrome 
  • Hormonal issues, in particular stemming from the brain or pituitary gland 
  • Having an underdeveloped reproductive system, or missing parts of your reproductive system 

Secondary amenorrhea causes:

  • In particular the ‘mini-pill’ (progesterone only), and certain IUDs 
  • Chemotherapy or radiation therapy 
  • Stress
  • Weight changes (major weight loss or weight gain)
  • Extreme and strenuous exercise 
  • Certain medications  

There are also medical conditions that can trigger amenorrhea, which can include:


  • Primary ovarian insufficiency (POI), also sometimes referred to as “decreased ovarian reserve,” is a condition in which your ovaries stop working before age 40. It is distinguished from natural menopause, according to ACOG, because around 5-10% of women with this condition will experience spontaneous conception and delivery.
  • Hypothalamic amenorrhea, which describes a condition in which your hypothalamus tells your body to stop producing GnRH, a hormone necessary for menstruation. This is commonly brought on by extreme undereating, stress, or excessive exercise.
  • Hormonal imbalances brought on by PCOS or hypothyroidism 
  • Ovarian tumors 
  • Obesity 
  • Chronic illness, such as IBS
  • Pituitary disorders, triggered by benign tumors on your pituitary gland, 

Getting your period back 

This journey can be easy or difficult depending on the underlying cause of one’s amenorrhea. 

To take the simplest example, for someone who is using the mini-pill which has caused their periods to stop, stopping taking the hormonal birth control will likely result in a consistent period within 3 months of coming off the pill.

For those with underlying medical reasons, such as PCOS or a severe eating disorder, getting a consistent period can be difficult. For the former group, balancing hormones can be one potential path as nutrition, lifestyle, and genetics all play a role in this reproductive condition, while for those in the latter group, psychotherapy combined with nutritional therapy and medical support can be a promising plan of action for some patients. 

Ultimately, though, how difficult it is to overcome amenorrhea is dependent on several factors, perhaps the most important of which is the underlying cause of the amenorrhea. It is for this reason that, if you suspect you have amenorrhea, or something feels off in your body, it is imperative you make an appointment with your primary care provider so they can investigate what is going on and work with you to create a treatment plan you’re comfortable with. 

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