Your period has stopped, but you're not pregnant? Discover the possible causes and learn how to restore your cycle naturally.

Key Facts About Missed Periods:

  • If you miss your period, you're usually not ovulating.
  • This means you can't get pregnant.
  • Over the long term, missed periods can lead to osteoporosis, heart problems, and mental health issues.
  • If you miss your period for more than 3 months and you're not pregnant, you should see a doctor.
  • If you're trying to conceive, hormone therapy or fertility treatments may be options.

No Period? Likely No Ovulation

Missed your period and wondering why? In many cases, an absent period signals a lack of ovulation. And without ovulation, pregnancy isn’t possible—a frustrating reality for those trying to conceive. If your period disappears for several months, it’s not just a fertility concern; it’s a potential red flag for your overall health.

While an occasional missed period isn’t unusual, about 5% of women who typically menstruate will experience amenorrhea (the medical term for absent periods) at some point in their lives.

In this article, we’ll explore the possible reasons behind a missed period, the different types of amenorrhea, the tests your doctor might recommend, and available treatments to help regulate your cycle.

How Does Menstruation Work?

Menstruation is a key part of the female menstrual cycle, designed to shed the uterine lining when pregnancy doesn’t occur. This process is regulated by a complex interplay of hormones.

If fertilisation doesn’t happen, progesterone levels drop. This signals the uterus to contract and shed its lining, leading to menstruation. These contractions can cause discomfort or even severe pain in the lower abdomen and back. At the same time, the cervix dilates slightly to allow menstrual blood to flow out.

What Is Amenorrhea?

Amenorrhea refers to the absence of menstruation and can be classified into two types:

  • Primary Amenorrhea – When a girl hasn’t started menstruating by age 16. This may result from congenital abnormalities in the reproductive system, chromosomal disorders like Turner syndrome (which affects approximately 1 in 2,500 girls), or hormonal imbalances.
  • Secondary Amenorrhea – When a woman who previously had regular periods stops menstruating for at least three months. This is the more common form and can have various underlying causes.

If menstrual cycles are infrequent, with gaps of more than 35 days between periods, this condition is known as oligomenorrhea.

Possible Causes of a Missed Period

A missed period can have many causes. While pregnancy is often the most obvious reason, hormonal, genetic, metabolic, and anatomical factors can also disrupt a normal cycle.

Primary Amenorrhea

In some cases, primary amenorrhea is caused by anatomical abnormalities or genetic conditions that affect the structure or function of the reproductive organs.

  • Turner Syndrome – A genetic disorder that affects only girls, where one X chromosome is missing or defective. This leads to underdeveloped ovaries and insufficient hormone production, preventing menstruation.
  • Mayer-Rokitansky-Küster-Hauser Syndrome (MRKH Syndrome) – A congenital condition where the uterus and, in some cases, the vagina are absent or underdeveloped. Since there is no uterine lining to shed, menstruation cannot occur, even though ovarian function is typically normal.
  • Congenital Adrenal Hyperplasia (CAH) – A genetic disorder that results in excess androgen (male hormone) production, disrupting sexual development. Depending on severity, this can prevent menstruation.
  • Cervical Atresia or Agenesis – If the cervix is missing or abnormally developed, menstrual blood cannot exit the uterus, leading to apparent amenorrhea.
  • Hymenal Atresia – A completely closed hymen (imperforate hymen) can block menstrual blood flow, causing blood accumulation (hematocolpos) and severe lower abdominal pain.
  • Uterine Malformations – Developmental abnormalities, such as a hypoplastic uterus (underdeveloped uterus), uterus didelphys (double uterus), or uterus unicornis (one-sided uterus), can impair or completely prevent menstruation.

Secondary Amenorrhea

Hormonal Disorders

  • Polycystic Ovary Syndrome (PCOS): PCOS is one of the most common causes of menstrual irregularities in young women.  It affects about 5-10% of women of childbearing age. It is characterised by an excess of male hormones, which can lead to irregular bleeding, acne, increased body hair, and difficulty conceiving.
  • Thyroid Disorders: Both an overactive thyroid (hyperthyroidism) and an underactive thyroid (hypothyroidism) can disrupt hormone balance and cause menstrual irregularities. A common form of hypothyroidism is Hashimoto's thyroiditis, an autoimmune disease in which the immune system attacks the thyroid gland. Thyroid diseases are relatively common, especially in women.
  • Hyperprolactinemia: An elevated prolactin level can suppress ovulation and lead to missed periods. This can be caused by medications, stress, or benign tumors of the pituitary gland (prolactinoma).
  • Hormonal Contraceptives: Birth control pills and other hormonal contraceptives can affect the menstrual cycle. Spotting or complete absence of menstruation may occur. This is especially true with low-dose pills or the use of long-acting contraceptives such as the hormone implant or the hormonal IUD.

Metabolic and Chronic Diseases

In addition to hormonal disorders, other chronic illnesses can also cause missed periods.

  • Poorly controlled blood sugar levels in diabetes can disrupt hormone balance.
  • Celiac disease, a gluten intolerance, leads to decreased absorption of nutrients that are important for the menstrual cycle.
  • Chronic inflammatory bowel diseases such as Crohn's disease and ulcerative colitis also affect the cycle through inflammation and nutrient deficiencies.
  • Severe kidney and liver diseases can also affect menstruation due to their influence on hormone balance and metabolism.

Psychological Causes

  • Pregnancy: Pregnancy is the most common cause of missed periods in women of childbearing age. A pregnancy test should always be the first step if a woman who has had unprotected sex misses her period.
  • Breastfeeding:  During breastfeeding, the hormone prolactin is released, which inhibits hormone production by the ovaries and suppresses ovulation. The duration of lactational amenorrhea varies from woman to woman and depends on the frequency and intensity of breastfeeding.
  • Menopause: With the onset of menopause, hormone production by the ovaries decreases, causing periods to become less frequent until they eventually stop altogether. The average age for the onset of menopause is 51, but it can start much earlier. Hot flashes, mood swings, and sleep disturbances are typical accompanying symptoms.

Lifestyle & Environmental Factors

  • Underweight: Anorexia or extreme underweight can impair ovarian hormone production and cause missed periods. Studies show that women with a BMI below 18.5 have a significantly increased risk of amenorrhea.
  • Overweight: Being significantly overweight can also disrupt hormone balance and cause menstrual irregularities. Obesity is a growing problem and affects more and more women of childbearing age.
  • Stress: Chronic stress can affect hormone production in the brain and disrupt the female cycle. Stress-related amenorrhea is particularly common in young women.
  • Competitive Sports: Extreme sports and intense training can affect hormone production and lead to missed periods. This is often seen in female athletes and dancers.
  • Rapid, Drastic Weight Loss: Even without being underweight, very rapid and massive weight loss can disrupt hormone balance and affect menstruation.
  • Eating Disorders: Eating disorders such as anorexia or bulimia can disrupt hormone balance and lead to missed periods.

Organic Causes

  • Endometriosis:  In endometriosis, tissue similar to the lining of the uterus grows outside the uterus. This can lead to severe menstrual pain, irregular bleeding, and in some cases, missed periods. Endometriosis is estimated to affect 5-10% of women of childbearing age.
  • Fibroids: Uterine fibroids are benign muscle tumors in the uterus. They can cause heavy menstrual bleeding, pain, and, in rare cases, missed periods.  Fibroids are very common, occurring in up to 70% of women.

Medication

Taking certain medications can also delay or suppress ovulation. Certain medications, such as antidepressants, antipsychotics, or chemotherapy drugs, can affect the menstrual cycle and lead to missed periods.

In this podcast, you will learn everything about possible reasons for a late or missed period:

What Can I Do About a Missed Period?

If you miss your period, it’s important to consult a gyneacologist to determine the cause. Your doctor will begin with a detailed medical history, asking about the regularity of your cycles, any existing health conditions, medications, and lifestyle factors. A physical examination will follow.

Diagnostic Tests

To identify the underlying cause, your doctor may recommend:

  • Hormone Tests – Measuring levels of oestrogen, progesterone, prolactin, thyroid hormones, and androgens.
  • Ultrasound Examination – To assess the uterus and ovaries for anatomical abnormalities.
  • Further Investigations – If needed, additional tests such as a hysteroscopy (to examine the uterine cavity) or laparoscopy (to assess the abdomen and pelvis) may be performed.

In this video, you will learn how to know if your periods are irregular and what you can do about it:

Treatment for a Missed Period

The treatment approach depends on the underlying cause:

  • Hormone Therapy – If hormonal imbalances are detected, treatment with oestrogen, progesterone, or other hormones can help restore regular cycles. Birth control pills may also be prescribed to regulate menstruation.
  • Medication – Conditions such as thyroid disorders or hyperprolactinemia are treated with targeted medications.
  • Lifestyle Changes – If weight fluctuations, excessive stress, or poor nutrition contribute to cycle irregularities, lifestyle adjustments—such as a balanced diet, regular exercise, and stress management—can help normalise menstruation.
  • Surgery – In rare cases, surgical intervention may be necessary, especially for conditions like fibroids, endometriosis, or anatomical abnormalities.

Home Remedies for a Regular Cycle

In addition to medical treatments, some natural remedies may help support cycle regulation:

  • Chasteberry (Vitex agnus-castus) – This medicinal herb is known to help balance hormones and regulate the menstrual cycle. Studies suggest it can be particularly effective for menstrual irregularities caused by elevated prolactin levels (latent hyperprolactinemia).
  • Regular Exercise – Moderate physical activity can positively influence hormone levels and improve menstrual regularity.
  • Stress Management – Techniques such as yoga, meditation, or progressive muscle relaxation can help reduce stress, which often contributes to cycle disruptions.

Missed Period and Fertility

For those trying to conceive, a missed period can be particularly distressing. Since ovulation is necessary for pregnancy, it’s crucial to identify and address the cause of amenorrhea.

If you're experiencing absent periods and want to conceive, your gyneacologist may recommend:

  • Hormone Therapy – Medications such as ovulation inducers can stimulate egg release.
  • Surgical Procedures – If anatomical issues (e.g., polyps, Asherman syndrome, or uterine malformations) are responsible, corrective surgery may be necessary.
  • In Vitro Fertilisation (IVF) – If other treatments are unsuccessful or the cause of amenorrhea cannot be resolved, assisted reproductive techniques such as IVF or ICSI may be an option.

Frequently Asked Questions About Missed Periods

Can I Get Pregnant Without a Period?

No, pregnancy is not possible without ovulation. A period usually indicates that ovulation has occurred and an egg has been released. Without ovulation, conception cannot happen.

When Does the Period Return After a Miscarriage?

Your period typically returns within 4 to 6 weeks after a miscarriage, but it may take longer for your cycle to regulate.

How Long Can a Missed Period Be Considered Normal?

If you’ve missed your period for more than three months and are not pregnant or breastfeeding, you should consult a doctor to determine the cause.

How Late Can a Period Be Before You Should Worry?

Slight fluctuations in your cycle are completely normal. A healthy menstrual cycle ranges from 21 to 35 days, and occasional delays are not unusual. However, if your period is more than three months late and pregnancy is ruled out, a medical evaluation is recommended.

What Are the Health Consequences of Missing a Period?

Beyond fertility concerns, prolonged amenorrhea can have significant health effects:

  • Lower Bone Density – Oestrogen is essential for bone health. Low oestrogen levels increase the risk of osteoporosis and fractures. A study on young women with hypothalamic amenorrhea (a dysfunction in the brain that affects hormone regulation) found they had significantly reduced bone density and a higher risk of fractures. Researchers emphasised the importance of oestrogen replacement therapy to prevent bone damage.
  • Increased Risk of Cardiovascular Disease – Oestrogen also supports heart health. A review found that exercise-induced amenorrhea can negatively impact cardiovascular function due to low oestrogen levels, counteracting the heart-protective benefits of exercise.
  • Mental Health Effects – Irregular or missing periods can contribute to mood swings, anxiety, and depression, as hormonal imbalances affect neurotransmitters that regulate emotions.

Takeaway: Early Diagnosis is Key

A missed period isn’t just about fertility—it’s an important indicator of overall health. Identifying the underlying cause early can prevent long-term health complications and improve well-being.

Concerned about an irregular cycle? Visit us at our fertility clinic in Zurich for a comprehensive evaluation.

Schedule your appointment today and let our experienced fertility specialists guide you on your journey to parenthood.