In short: Every woman’s cycle is unique — but it helps to know when a change in your period is a “normal fluctuation” and when it is a “warning sign worth investigating.” This article explains the main causes of irregular periods, when you should see a doctor, and how they are diagnosed and treated, in plain language.

What does a normal menstrual cycle look like?

A healthy cycle usually lasts between 21 and 35 days, with bleeding for 2–7 days. It is completely normal for your cycle length to shift by a few days from month to month. We call it “irregular” when cycles become noticeably shorter or longer, when bleeding is much heavier or lighter than usual, or when periods stop altogether.

The main causes of irregular periods

• Hormonal imbalances: One of the most common causes is polycystic ovary syndrome (PCOS), where irregular ovulation disrupts the cycle.
• Thyroid problems: An underactive or overactive thyroid directly affects menstrual regularity.
• Stress, sudden weight change and intense exercise: When the body’s energy balance is disturbed, it may temporarily “postpone” reproductive hormones.
• Age-related phases: The first years after puberty and the perimenopausal transition naturally come with some irregularity.
• Structural causes: Uterine polyps, fibroids or ovarian cysts can change bleeding patterns.
• Medications and contraception: Some medicines and hormonal methods can affect the cycle.

When should you see a doctor?

The following are warning signs that should be evaluated without delay:

• Your cycle is consistently shorter than 21 days or longer than 35 days,
• Bleeding lasts more than 7 days or is heavy enough to soak a pad every hour,
• You have spotting between periods or bleeding after intercourse,
• You have not had a period for 3 months or more (and are not pregnant),
• Severe pelvic pain, fatigue or palpitations accompany your period.

Also, if you are planning to have a child and your periods are irregular, early evaluation matters, because this may point to an ovulation problem.

Which tests are used for diagnosis?

Assessment usually begins with a detailed history and examination. When needed, we add: pelvic ultrasound to view the uterus and ovaries, hormone tests (such as thyroid hormones, prolactin, and AMH, which reflects ovarian reserve), and sometimes further tests to evaluate the inside of the uterus. The goal is to find the true cause behind the irregularity.

How is treatment planned?

Treatment is tailored to the underlying cause. Sometimes lifestyle adjustments (weight, nutrition, stress management) are enough to restore the cycle. Hormonal causes may call for medication, while structural problems may require minimally invasive (laparoscopic or hysteroscopic) procedures. For patients who wish to conceive, treatment is shaped around restoring ovulation and the goal of pregnancy.

In summary

Occasional small shifts are usually harmless; but persistent irregularity may be your body signaling something. Early evaluation both catches a possible problem in time and, if you wish to have a child, helps map out the right path.

If irregular periods are worrying you, you can contact us for an assessment, explore our treatment options, or read our guide on the IVF process. Prof. Dr. Murat Arslan and his team are here for you at Biruni University Hospital.