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Irregular Periods: Causes, Tests and Treatment in Seoul
Quick answer: Irregular periods are cycles that are shorter than 24 days, longer than 38 days, or vary widely from month to month. Common causes include stress, weight change, PCOS, thyroid problems, and perimenopause. At Eunice Women's Clinic near Seongsu Station, Dr. Eun Mi-na, an English-speaking female OB-GYN, uses history, ultrasound, and blood tests to find the cause.
What counts as an irregular period?
A menstrual cycle is counted from the first day of one period to the first day of the next. For most adults, a normal cycle is about 24 to 38 days, and the length usually varies by no more than 7 to 9 days from cycle to cycle. Your cycle may be considered irregular if:
- Your periods come more often than every 24 days
- Your periods come less often than every 38 days
- The length of your cycle changes a lot from month to month
- You bleed between periods
- You have no period for 3 months or more (when not pregnant)
Cycles are often irregular in the first few years after periods start and in the years before menopause.
What causes irregular periods?
- Pregnancy (always rule this out first)
- Stress, travel, time-zone changes, and a new environment (see our guide on period changes after moving abroad)
- Large weight changes, intense exercise, or eating disorders
- Polycystic ovary syndrome (PCOS)
- Thyroid disorders or high prolactin levels
- Perimenopause
- Hormonal contraception, including starting, stopping, or missing pills
- Structural causes such as polyps, fibroids, or adenomyosis
- Some medicines
What symptoms may come with irregular periods?
Depending on the cause, you may also notice acne or extra hair growth (PCOS), hot flashes (perimenopause), weight change, tiredness, feeling hot or cold (thyroid), or milky nipple discharge (high prolactin).
When should I see a doctor?
- You have had no period for 3 months, or fewer than about 8 periods in a year
- Periods come more often than every 3 weeks
- You bleed between periods or after sex
- Bleeding lasts more than 7 days or is very heavy
- You are trying to become pregnant
- You have any bleeding after menopause
Seek emergency care (call 119) if you have very heavy bleeding with dizziness or fainting, or severe abdominal pain, especially if you might be pregnant.
How are irregular periods evaluated at the clinic?
Bring a record of your recent period dates if you have one; a period-tracking app is helpful. Dr. Eun will usually start with a pregnancy test. A transvaginal ultrasound or a pelvic ultrasound checks the uterus, uterine lining, and ovaries. Blood tests may include hormones, thyroid function, and prolactin, and sometimes an AMH test.
What are the treatment options?
Treatment depends on the cause and your goals.
- Lifestyle factors: managing stress, sleep, and weight can help cycles return to normal.
- Hormonal treatment: combined hormonal contraceptives or cyclic progestin can regulate bleeding and protect the uterine lining.
- Treating the cause: for example, thyroid treatment or management of PCOS.
- Pregnancy planning: ovulation induction may be discussed if you are not ovulating regularly.
Individual results vary.
Getting care in English near Seongsu Station
Eunice Women's Clinic is on the 8th floor of Bethel Place, 120 Achasan-ro, Seongdong-gu, Seoul. The building is across the crosswalk from Seoul Subway Line 2 Seongsu Station Exit 3, about a 1-minute walk ( directions). Dr. Eun Mi-na, a female board-certified OB-GYN, holds consultations about irregular periods in English.
| Day | Hours |
|---|---|
| Mon, Wed, Fri | 10:00–19:00 (lunch 13:30–14:30) |
| Tue, Thu | 10:00–20:00 (lunch 13:30–14:30) |
| Sat | 10:00–14:00 (no lunch break) |
| Sun and public holidays | Closed |
Booking is recommended. You can book through Naver Booking, the KakaoTalk channel (search "유니스산부인과"), or by phone at +82-2-467-3100 ( how to book). Call or message to check same-day availability.
Book an appointment in English
Eunice Women's Clinic · 8F Bethel Place, 120 Achasan-ro, Seongdong-gu, Seoul · Seongsu Station (Line 2) Exit 3
Phone: +82-2-467-3100 · KakaoTalk channel · Naver Booking
Mon, Wed, Fri 10:00–19:00 · Tue & Thu 10:00–20:00 · Sat 10:00–14:00 · Lunch 13:30–14:30 · Closed Sundays & public holidays
Frequently asked questions
Can moving to Korea make my periods irregular?
Yes. Stress, jet lag, a new diet, changes in sleep, and changes in exercise can all affect hormone signals and delay or change periods. This often settles within a few cycles. If it continues for 3 months or more, see a doctor.
How late can a period be before I should worry?
A period that is more than a week late should be checked with a pregnancy test. If the test is negative and you still have no period after 3 months, or if your cycles stay irregular, see a gynecologist to look for causes such as stress, thyroid problems, or PCOS.
Is it normal to have two periods in one month?
It can happen if your cycle is short, such as 24 days. However, bleeding more often than every 3 weeks, or bleeding between periods, should be checked to look for causes such as polyps, hormone changes, or infection.
Do I need blood tests for irregular periods?
Often, yes. Blood tests can check hormones, thyroid function, and prolactin. The doctor chooses which tests are needed based on your age, symptoms, and history, and usually combines them with an ultrasound of the uterus and ovaries.
Can irregular periods affect fertility?
Irregular periods may mean you are not ovulating regularly, which can make it harder to become pregnant. Many causes, such as PCOS and thyroid problems, are treatable. If you plan to conceive, mention this at your visit so the doctor can plan tests.
Related pages
This page provides general health information for patients and does not replace a consultation with a doctor. Individual results vary. If you have severe pain, heavy bleeding, fainting or other urgent symptoms, call 119 or go to the nearest emergency room. Page updated September 2026.