This refers to menstrual pain that occurs in the absence of any underlying gynecological disease. Most cases of menstrual pain fall into this category.

It typically begins 2–5 years after menarche (the first menstrual period). The pain usually starts one to two days before menstruation or on the first day, then gradually decreases, resolving within approximately 12 to 72 hours.

The pain is mostly located in the central lower abdomen, though some individuals may also experience lower back pain or thigh pain.
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The nature of the pain can be either a constant dull ache or intermittent cramping pain, and it is often accompanied by symptoms such as nausea, diarrhea, headache, and general fatigue.
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Secondary dysmenorrhea can present similarly to primary dysmenorrhea, but it is caused by underlying gynecologic conditions such as endometriosis, adenomyosis, or uterine fibroids.
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A key point to note is that primary dysmenorrhea is typically centered along the midline of the body. Therefore, if the pain is localized more to one side, secondary dysmenorrhea should be considered. The timing of pain may also occur outside of menstruation.

Additionally, the onset of menstrual pain after the age of 25, or the presence of abnormal vaginal bleeding—such as heavy menstrual bleeding or intermenstrual bleeding—should raise suspicion for secondary dysmenorrhea.

Most women cannot identify a specific cause for their menstrual pain. However, studies have found that primary dysmenorrhea is associated with the following factors:

・ Young age :Primary dysmenorrhea is more common in individuals under 30 and tends to decrease with age.
・ Low BMI : Individuals with a BMI below 20 kg/m² are more likely to experience primary dysmenorrhea.
・ Smoking : Statistical data show that smokers are more likely to have primary dysmenorrhea, and the risk increases with the amount smoked.
・ Early menarche : Those who had their first menstrual period before age 12 are more likely to develop primary dysmenorrhea.
・ Longer menstrual cycles and duration
・ Heavy menstrual flow
・ Nulliparity : Individuals who have not given birth are more likely to experience menstrual pain; studies also suggest that the younger the age at first childbirth, the lower the likelihood of dysmenorrhea later.

Other factors such as genetic predisposition, diet, emotional state, and lifestyle habits have not shown statistically significant associations with primary dysmenorrhea.

For individuals with primary dysmenorrhea, the main goal of treatment is pain control, so that daily work and activities are not significantly affected. Physicians typically begin with a basic medical history, physical examination, and, if necessary, imaging studies to rule out secondary dysmenorrhea, and then proceed with treatment based on clinical experience. However, menstrual pain is highly subjective, so patients may choose different treatment options depending on the severity of their symptoms.
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Heat therapy: Research suggests that applying heat to the lower abdomen can relieve menstrual pain. Its effectiveness is comparable to ibuprofen and may even be more effective than acetaminophen. Although heat therapy can be somewhat inconvenient, it helps avoid potential medication side effects. It is a good option for those who prefer not to take medication. Additionally, some studies indicate that combining heat therapy with oral medication may provide faster pain relief.
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Exercise and sexual intercourse : Some small studies suggest that exercise may help relieve menstrual pain, although the level of evidence is limited. Activities such as yoga, sexual intercourse, and orgasm may also help in some individuals, but the effects vary from person to person.
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Behavioral therapy : This includes techniques such as progressive muscle relaxation, pain management training, and relaxation combined with biofeedback. These approaches may help alleviate symptoms, but current evidence remains inconclusive.
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Diet and supplements : Most studies on dietary interventions for menstrual pain are small, and strong evidence is lacking. Some proposed options include:
・ Low-fat vegetarian diet
・ Dairy intake
・ Ginger: 750–2000 mg daily during the first 1–3 days of menstruation
・ Vitamin E: 500 IU daily, starting 2 days before menstruation and continuing until day 3 of menstruation
・ Vitamin B1:100mg of vitamin B1 daily
・ Vitamin B6:200mg of vitamin B6 daily
・ Fish oil supplies
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Currently, there is substantial research and strong evidence supporting pharmacologic treatment for primary dysmenorrhea. The two main treatment options widely recognized as effective are nonsteroidal anti-inflammatory drugs (NSAIDs) and hormonal contraceptives. However, there is no clear conclusion as to which of these two approaches is more effective.

In clinical practice, treatment is usually started based on the patient's needs and preferences. If one approach is ineffective, the other may be tried. For patients who do not respond well to either therapy alone, combination treatment can also be considered.

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): Numerous large-scale studies support the effectiveness of NSAIDs in treating menstrual pain. However, there is still no definitive conclusion regarding comparative efficacy and safety among different types of NSAIDs, or clear guidelines on how to select a specific NSAID.

‍Hormonal Contraceptives: Combined estrogen–progestin contraceptives suppress ovulation and cause the endometrium to become thinner over time. A thinner endometrium contains relatively fewer precursors involved in prostaglandin synthesis. These endometrial changes reduce menstrual bleeding and uterine contractions during menstruation, thereby alleviating dysmenorrhea.

Abnormal menstruation frequently troubles many women and is one of the most common reasons for seeking care in gynecology. However, it does not refer to a single disease; rather, it is a general term for abnormalities in the menstrual cycle, duration of menstruation, or amount of bleeding. If you notice any irregular menstrual symptoms, it is recommended to schedule a medical consultation and inform your doctor about your condition. This allows for professional evaluation and appropriate treatment, helping to avoid delays in receiving care.

Normal menstrual cycle, but with heavy bleeding or prolonged duration
・ Uterine fibroids
・ Adenomyosis
・ Coagulation disorders

Normal menstrual cycle, but abnormal bleeding between periods
・ Endometrial polyps
・ Cervical polyps
・ Endometritis

Irregular menstruation (cycle length, duration, and flow may vary)
・ Ovulatory dysfunction
・ Polycystic ovary syndrome (PCOS)
・ Hyperprolactinemia
・ Thyroid disease

Absence of menstruation for more than 3–6 months
・ Ovulatory dysfunction
・ Hypothalamic secondary amenorrhea
・ Premature ovarian insufficiency
・ Intrauterine adhesions

Abnormal uterine bleeding
・ Abnormal pregnancy or pregnancy-related complications: such as early pregnancy, threatened abortion, ectopic pregnancy, molar pregnancy, etc.
・ Malignancies: endometrial cancer, cervical cancer, ovarian cancer, etc.
・ Genital tract infections: cervicitis, endometritis, atrophic vaginitis
・ Improper medication use: incorrect use of oral contraceptives or emergency contraception
・ Foreign bodies: such as displaced intrauterine devices (IUDs)

The primary cause is dysfunction of the menstrual regulatory system (the hypothalamic–pituitary–ovarian axis), leading to anovulation or insufficient luteal function. This is commonly seen in adolescent girls, women in the menopausal transition, and women of reproductive age.
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・ Intense exercise
・ Eating disorders
・ Stress
・ Idiopathic hypogonadotropic hypogonadism
・ Hyperprolactinemia
・ Lactational amenorrhea
・ Pituitary adenoma or other pituitary tumor
・ Other conditions:
- Polycystic ovary syndrome
- Hyperthyroidism or hypothyroidism; hormone-secreting tumors (adrenal or ovarian)
- Chronic liver or kidney disease
- Cushings disease
- Premature ovarian insufficiency, which may be autoimmune, genetic, surgical/idiopathic, or related to medications or radiation
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