Photography via Unsplash+. Stock photo. Posed by model.
Why did my period stop?
Amenorrhea causes and next steps
Top things to know:
A missing period is called amenorrhea
Primary amenorrhea is when a first period has not arrived by age 15 or within three years of breast development
Secondary amenorrhea is when someone who previously had periods stops having them
Amenorrhea is usually a sign of something else happening in the body rather than a condition itself—whether periods return depends on the underlying cause
Tracking your cycle in the Clue app helps you and your healthcare provider spot patterns. Clue’s Report for your Doctor turns your cycle history into a printable summary you can bring to your appointment
What is amenorrhea?
If you’re wondering, “Why did my period stop?” you’re not alone—and in most cases, there’s an answer.
Amenorrhea is the absence of menstrual periods (1-3). It is not a disease itself. It usually signals something else going on in the body, such as a hormonal change, health condition, or medication (4).
The menstrual cycle is more than just the period. It involves both the ovarian cycle (changes in the ovaries) and the uterine cycle (changes in the uterus). The whole process is driven by a coordinated chain of hormonal signals between the brain, ovaries, and uterus (5).
Types of amenorrhea
There are two types of amenorrhea: primary and secondary (1-3).
Type | What it means |
|---|---|
Primary | When a first period has not arrived by age 15 or within three years of the start of breast development (3,6). |
Secondary | Three months without a period, or six months if cycles were unpredictable before |
The rest of this article focuses on secondary amenorrhea.
When a missing period may be expected
Pregnancy, breastfeeding (lactational amenorrhea), and menopause are expected reasons for periods to stop (7). Some hormonal contraceptives can also make bleeding very light or stop it altogether (7).
If pregnancy is possible, taking a pregnancy test is an important first step. Once you've ruled out pregnancy, breastfeeding, and menopause, a missing period is usually a sign of something else going on in the body (1).
Why did my period stop? Common amenorrhea causes
Common causes include functional hypothalamic amenorrhea (FHA), PMOS, thyroid disorders, high prolactin levels, primary ovarian insufficiency (POI), uterine scarring, certain medications, and hormonal birth control (1-3,7).
Functional hypothalamic amenorrhea (FHA)
FHA is a common cause of amenorrhea, particularly among adolescents and younger adults (8). It happens when the hormonal communication network between the brain and ovaries—the hypothalamic-pituitary-ovarian (HPO) axis—is suppressed. This can interrupt ovulation (the release of an egg), causing periods to become unpredictable or stop (1,8-10).
Common triggers include not eating enough to meet the body’s energy needs (low energy availability), intense exercise, rapid weight loss, or prolonged stress (1,3,8).
FHA is often seen in athletes and people with restrictive eating patterns, but it can affect anyone whose body is under sustained physical or psychological stress (3,8).
Left untreated, FHA can lead to low estrogen levels. Over time, low estrogen can reduce bone density and affect heart health, as well as fertility (3,9,11).
Treatment focuses on addressing the underlying cause and restoring adequate energy availability (3,8). This may involve eating more, adjusting exercise, managing stress, and taking supplements when needed (3,8). Support from a team that includes healthcare providers, dietitians, and mental health professionals may be helpful (3).
Polyendocrine metabolic ovarian syndrome (PMOS)
PMOS (formerly polycystic ovary syndrome, or PCOS) is one of the most common causes of secondary amenorrhea and the leading cause of infertility related to irregular ovulation (1,3,7,9, 12).
Diagnosis involves a menstrual and symptom history, hormone testing, and may include hormone and metabolic blood tests or a pelvic ultrasound. In adults, PMOS is usually diagnosed when at least two of the following three features are present, after other possible causes have been excluded (12,13):
Irregular or absent periods caused by irregular ovulation
Signs of higher androgen levels. Androgens are hormones, such as testosterone, that are present in everyone. Higher levels can cause excess facial or body hair or acne
Polycystic ovarian morphology on ultrasound (often called “cysts”)
Not everyone with PMOS has all three features, and an ultrasound is not always needed. Different diagnostic criteria apply to adolescents, for whom ultrasound is not recommended as part of diagnosis (12,13).
Irregular ovulation can cause periods to become unpredictable or stop. Insulin resistance (when the body doesn't respond well to insulin, the hormone that controls blood sugar) and low-grade inflammation are also common in people with PMOS and can worsen symptoms (12).
Treatment depends on a person’s symptoms and reproductive goals. It may include hormonal contraception, insulin-sensitizing or anti-androgen medications, and lifestyle changes, such as diet and exercise (1,3,7,13).
Thyroid disorders
The thyroid gland produces hormones that help regulate the menstrual cycle. Both an underactive thyroid (hypothyroidism) and an overactive thyroid (hyperthyroidism) can disrupt the HPO axis and affect ovulation, leading to irregular or absent periods (1,3,4).
A blood test measuring thyroid-stimulating hormone (TSH) can help identify thyroid issues. A healthcare provider may also gently feel the neck to check the thyroid (4). Treatment depends on the condition.
Hypothyroidism is usually treated with thyroid hormone replacement medication, while treatment for hyperthyroidism may include thyroid-blocking medications, radioactive iodine therapy, ablation, or surgery (4).
Learn more about hypothyroidism and hyperthyroidism and the menstrual cycle.
High prolactin levels (hyperprolactinemia):
Prolactin is the hormone responsible for milk production (14). High prolactin levels outside of pregnancy and breastfeeding can suppress the HPO axis, as they do during breastfeeding. This can interrupt ovulation and cause periods to become irregular or stop (3,4,15).
Possible causes include certain medications, such as antipsychotics, some antidepressants, and opioids, as well as hypothyroidism, chronic kidney disease, and a usually noncancerous pituitary growth called a prolactinoma (3,4,15).
Some people may notice unexpected milky nipple discharge (galactorrhea). This is an important symptom to mention to a healthcare provider (3,4,14,15). Diagnosis involves a blood test for prolactin levels and, if elevated, an MRI of the pituitary gland (3,4,15).
Treatment depends on the cause. A prolactinoma is usually treated with medication and, in some cases, surgery. When a medication is causing high prolactin, a healthcare provider may recommend changing it. Do not stop or change a prescribed medication without speaking with the person who prescribed it (3,4,15).
Primary ovarian insufficiency (POI)
POI, sometimes called premature ovarian insufficiency, happens when the ovaries stop working as expected before age 40. It can cause absent or infrequent periods (2,4,7). POI may be linked to genetic or autoimmune conditions or damage to the ovaries from radiation, chemotherapy, infection, or surgery. In many cases, however, no specific cause is identified (4,7).
Structural changes in the uterus
Asherman's syndrome (also called intrauterine adhesions or intrauterine synechiae) happens when scar tissue forms inside the uterus or cervix. This can prevent the uterine lining from building up, so there is nothing to shed (and no period) (4,16).
This may happen after uterine surgery (such as a dilation and curettage, a procedure to remove tissue from the uterus), a missed or incomplete miscarriage, placenta tissue left in the uterus after birth, or, less commonly, uterine infection from tuberculosis or schistosomiasis (1,4,16).
Healthcare providers usually consider Asherman's syndrome after ruling out hormone-related causes, and may confirm it with imaging or a procedure that allows them to look inside the uterus. Surgical removal of the scar tissue is the main treatment (4).
Certain medications and treatments
Several medications and treatments can suppress or stop periods as a side effect. These include (3,7,15):
Chemotherapy and radiation therapy
Antipsychotics, certain antidepressants, and opioids, which may raise prolactin levels
Some blood pressure medications
Some recreational drugs
Smoking may also be associated with a higher risk of amenorrhea (2).
When speaking to a healthcare provider about a missing period, mention all medications and substances you take, including those that are prescribed, over-the-counter, or recreational.
Hormonal birth control
Some types of hormonal contraception, such as birth control pills, the shot, the implant, or hormonal intrauterine devices (IUDs), may cause very light bleeding, unpredictable bleeding, or amenorrhea (1,2).
These methods can affect ovulation or thin the uterine lining. This means there may be little or no lining to shed, including during the hormone-free week of some birth control pills (4,15). This is an expected effect of some hormonal contraceptives and is not usually a sign that something is wrong (4).
Periods and ovulation may take some time to return after stopping hormonal contraception. Speak with a healthcare provider if you are concerned, if pregnancy is possible, or if your periods have not returned within three months of stopping, as the contraception may have been masking an underlying condition (1). It can take longer after stopping the contraceptive shot.
What does a missing period mean for fertility?
Amenorrhea does not automatically mean that someone is infertile. Its effect on fertility depends on the underlying cause, and many causes are treatable (1–3).
For people trying to become pregnant, the cause matters:
FHA: Ovulation and fertility typically return when the underlying energy deficit, exercise load, or stress is addressed (8)
PMOS: Treatments that support ovulation are effective for many people. The most appropriate option depends on someone’s age, health, reproductive goals, and whether other fertility factors are present (17)
Other hormonal causes (such as thyroid disorders or high prolactin): Treating the underlying condition can often restore ovulation (2-4)
POI or structural causes: Specialist assessment may be needed to understand how the condition could affect fertility and which options are available
Anyone who is trying to become pregnant and is not having periods should speak with a healthcare provider rather than waiting for the usual infertility assessment timeframe. A reproductive specialist can assess what is happening and discuss the available options (1,2).
When to see a healthcare provider
Speak with a healthcare provider if a period has been missing for three or more months, or six or more months for people whose cycles were unpredictable before (1-3). You can seek advice sooner if you are concerned.
If pregnancy is possible, take a pregnancy test rather than waiting three months.
Signs to get checked sooner
It’s worth speaking with a healthcare provider sooner if the missing periods occur alongside other symptoms, such as milky nipple discharge when you are not breastfeeding, significant weight changes, pelvic pain, new headaches or changes in vision, or new signs of higher androgen levels, such as excess facial or body hair (3).
Risks of long-term amenorrhea
Finding the cause matters because the possible long-term effects of amenorrhea depend on what is causing it (4).
For some people, long-term amenorrhea may affect:
Bone density: Prolonged low estrogen levels can speed up bone loss and increase the risk of osteoporosis and fractures ( 11)
Cardiovascular health: Prolonged low estrogen is linked to increased risk of heart disease (11)
Fertility: Amenorrhea can make pregnancy less likely while ovulation is not happening, although its long-term effect on fertility depends on the cause (1,4)
The uterine lining: When amenorrhea is caused by chronic irregular ovulation, including in some people with PMOS, the uterine lining can become too thick over time
How is amenorrhea diagnosed?
There is no single test for amenorrhea. Diagnosis combines a person’s history, a physical examination, imaging, and test results (3,4).
Diagnosing amenorrhea starts with a detailed conversation. A healthcare provider will ask about your menstrual history, health history, weight or exercise changes, medications, and family history (1,3).
A pregnancy test is always one of the first steps (1,3). From there, a healthcare provider may order blood tests (such as thyroid function and prolactin levels) and, depending on the results, imaging such as a pelvic ultrasound or MRI (3,4).
Your cycle history helps your healthcare provider see when your period stopped and what changed beforehand. Tracking with Clue can make this conversation easier.
Using Clue to track a missing period
Tracking your cycle in the Clue app can help you notice when your period is late and how long it has been missing. You can track your period days alongside experiences such as pain, fatigue, and mood changes.
You can generate a report of your menstrual cycle statistics and tracking history to bring to healthcare appointments. This can help you explain when your period stopped, how your cycles changed beforehand, and whether you noticed any related symptoms.
FAQs
Will my period return?
Whether your period returns depends on why it stopped. For many people, periods return once the underlying cause is addressed, although the timeframe varies (1–3).
Some causes may require longer-term treatment or specialist care. Speak with a healthcare provider if you have gone three months without a period, or sooner if pregnancy is possible or you have other symptoms that concern you.
How can I prevent amenorrhea?
Some causes (such as PMOS, thyroid disorders, POI, and Asherman's syndrome) can’t be prevented (1,7). Eating enough to meet your body’s needs, staying active without overtraining, and getting support for ongoing stress or disordered eating may reduce the risk of FHA (3,8).
Tracking your cycle consistently in the Clue app can help you notice changes early and seek advice sooner (1,3).
