Which department should I see for irregular periods?

Name: Which department should I see for irregular periods?
Creator: Which Department
Published: 2026-09-16

2026-09-16 · Neutral information that names no hospital, doctor or region. No rankings, recommendations or reviews.

Short answer

Obstetrics & Gynecology(산부인과) is generally the first department to see for irregular periods, as gynecologists specialize in menstrual cycle disorders and their underlying causes. In some cases, if a hormonal gland issue such as thyroid or pituitary dysfunction is suspected, your gynecologist may refer you to Internal Medicine — Endocrinology(내과·내분비내과) for further evaluation.

Which department

1Obstetrics & Gynecology (산부인과)
Gynecologists are trained to evaluate the full range of causes behind irregular periods, including hormonal imbalance, ovarian conditions, uterine structural issues, and reproductive health factors. This department handles both the initial workup and ongoing management of menstrual cycle irregularities. — First / second line: A local women's clinic or gynecology clinic (의원) is generally the appropriate first stop for most people with irregular periods. Referral to a larger hospital (병원·종합병원) may follow if imaging or specialized procedures are needed.
2Internal Medicine – Endocrinology (내과·내분비내과)
Conditions affecting hormone-producing glands — such as thyroid disorders, hyperprolactinemia, or adrenal issues — can directly disrupt the menstrual cycle. An endocrinologist evaluates and manages these systemic hormonal causes. — First / second line: This department is typically seen after a gynecologist identifies a possible hormonal gland abnormality, or if you already have a known endocrine condition that may be affecting your cycle. Direct first visits are less common unless a systemic hormonal disorder is already suspected.
3Pediatrics & Adolescent Medicine (소아청소년과)
For adolescents whose menstrual cycles have not yet stabilized after menarche, a pediatrician or adolescent medicine specialist familiar with puberty-related hormonal development may be involved alongside a gynecologist. — First / second line: This applies mainly to patients under roughly 18 who are more comfortable in a pediatric setting; many adolescents are also seen directly at gynecology clinics that handle adolescent patients.

Go to the ER / call 119 if

If any of the following applies, do not choose a department — go to an emergency room or call 119 (Korea's emergency number).

Sudden, very heavy bleeding that soaks through a pad or tampon every hour for two or more consecutive hours.
Severe abdominal or pelvic pain that comes on suddenly and does not ease, especially with dizziness or fainting.
Signs of significant blood loss such as extreme paleness, rapid heartbeat, confusion, or loss of consciousness.
Suspected pregnancy combined with sharp one-sided pelvic pain and vaginal bleeding, which may suggest an ectopic pregnancy.
High fever (generally above 38.5°C / 101.3°F) together with pelvic pain and unusual vaginal discharge.

Before your visit

Note the dates of your last several periods, including when each started and ended, so you can describe the pattern clearly.
Estimate how heavy or light your flow has been compared to your usual baseline, and whether you have noticed clotting or spotting between periods.
List any other symptoms that appeared around the same time, such as unusual hair growth or loss, acne, weight changes, fatigue, or nipple discharge.
Bring a list of all medications, supplements, and herbal products you are currently taking, including any hormonal contraceptives.
If you have had any previous blood tests, ultrasound results, or gynecology records, bring copies or have them accessible.
Think about any major recent life changes such as significant stress, sudden weight loss or gain, intense exercise, or recent travel, as these can affect the menstrual cycle.

General principles

Irregular periods — meaning cycles that are significantly shorter, longer, heavier, lighter, or more unpredictable than a person's usual pattern — can have many different underlying causes. Because the menstrual cycle is controlled by a chain of hormonal signals involving the brain, pituitary gland, ovaries, and uterus, disruption at any point in that chain can alter the cycle.

Obstetrics & Gynecology is generally considered the primary specialty for evaluating menstrual irregularities because gynecologists are trained to assess both structural factors (such as uterine or ovarian conditions) and hormonal factors within the reproductive system. Depending on initial findings, a gynecologist may coordinate with other specialists or refer for additional evaluation.

In the Korean healthcare system, it is generally possible to visit a local gynecology clinic (의원) directly without a referral for this type of concern. If more advanced imaging, procedures, or specialist input is needed, the clinic will typically provide a referral letter (진료의뢰서) for a larger hospital. National Health Insurance (건강보험) generally covers gynecology consultations, though coverage details for specific tests depend on the clinical situation.

The general diagnostic approach for irregular periods usually begins with a thorough history and may involve blood tests to check hormone levels and a pelvic examination or ultrasound — the specific tests appropriate for any individual are determined by the consulting doctor based on that person's history and symptoms.

FAQ

Should I go to a local clinic (의원) or a larger hospital for irregular periods?

For most people, a local gynecology clinic is generally the appropriate starting point, as the initial evaluation can usually be carried out there. A referral to a larger hospital is typically arranged by the clinic if more specialized tests or procedures are indicated based on what the doctor finds.

Could irregular periods be a sign of something other than a gynecological issue?

Yes — systemic conditions such as thyroid disorders, elevated prolactin levels, or significant nutritional and weight changes can all affect the menstrual cycle. A gynecologist will generally consider these possibilities during the initial evaluation and may refer to an endocrinologist or another specialist if a non-gynecological cause is suspected.

What kinds of tests are generally done for irregular periods?

The tests considered appropriate vary by individual and are decided by the consulting doctor. Generally speaking, the evaluation may include blood hormone level checks and pelvic imaging such as an ultrasound; the specific combination depends on the patient's age, symptoms, and history as assessed during the consultation.

Is the approach different for teenagers versus adults?

Adolescents who have recently started their periods often have naturally irregular cycles as the hormonal system matures, so the clinical interpretation can differ from that for adults. Both gynecology clinics and adolescent-focused practitioners can be appropriate for younger patients; the consulting doctor will factor age and stage of development into the assessment.

Find a clinic (external directories)

External directories for finding a clinic by region once you know the department (public data, no rankings or recommendations).

Hospital directory by region (koreahospital.org)

This page is general medical information and does not replace diagnosis, treatment or choosing a clinic. Consult a doctor for any symptom. In an emergency, go to the ER or call 119 immediately.