SYMPTOMS

What is considered a delayed period?

Menstruation refers to the periodic shedding and bleeding of the endometrial lining in women. The normal menstrual cycle for women typically ranges from 21 to 35 days, with an average of 28 days. Each woman has her own menstrual cycle, which varies in length^[1].

For women with regular menstrual cycles, a delay of more than 7 to 9 days is generally considered a delayed period.

The medical definition of a delayed period takes the patient's age into account, as follows:

• 18-25 years: A delay of > 9 days in the menstrual cycle length;
• 26-41 years: A delay of > 7 days in the menstrual cycle length;
• 42-45 years: A delay of > 9 days in the menstrual cycle length;
• Patients under 18 or over 45 also fall under the > 9-day delay definition, though evidence for normal fluctuation ranges in these groups is less clear^[3].

The menstrual cycle is regulated by the body's endocrine hormones. When various factors disrupt hormone levels or affect the uterus, it can lead to a delayed period.

Delayed periods may occur repeatedly, occasionally, or irregularly^[1]. Women of reproductive age should first rule out pregnancy, followed by further medical history collection, physical examination to identify potential triggers, and hormone level testing if necessary.

How long must a period be delayed to be considered amenorrhea?

Delayed periods generally do not exceed six months. For women with previously regular cycles, the absence of menstruation for over 3 months, or for women with irregular cycles, the absence for over 6 months, is termed secondary amenorrhea^[1].

Is a delayed period normal?

It depends. If only one menstrual cycle is missed, medical evaluation may not be necessary.

However, if amenorrhea lasts for 3 months or longer, or if periods are infrequent (fewer than 9 cycles per year or cycles longer than 35 days), the patient should undergo examination.

TREATMENT

How many days of delayed menstruation can detect pregnancy?

If you have had unprotected sex recently and your period is delayed for more than 10 days, you can purchase a pregnancy test kit to check for pregnancy^[1].

What should I do if my period is delayed?

• If you have had unprotected sex recently and your period is delayed for more than 10 days, first test for pregnancy.
• Discontinue the use of progesterone-containing medications or other health supplements with unknown ingredients.
• Maintain a healthy and balanced diet, exercise more, control your weight, avoid staying up late, and keep a regular daily routine.
• Stay positive, adjust your emotions, and maintain a happy work and life.
• Use contraception to avoid multiple abortions.
• Keep warm and avoid prolonged exposure to cold.

It is important to note that if these measures do not alleviate the delayed menstruation or if the delay worsens, you should seek medical attention promptly to determine the cause and receive targeted treatment.

DIAGNOSIS

Under what circumstances should you seek medical attention for a delayed period?

If a delayed period is accompanied by the following conditions (not limited to these), you should seek medical attention immediately:

• Recent unprotected sexual activity with a period delay exceeding 10 days;
• Fatigue, drowsiness, nausea, vomiting, etc.;
• Obesity, excessive hair growth, acne, infertility, etc.;
• Loss of appetite, slowed reactions, apathy, constipation, etc.;
• Galactorrhea, headaches, blurred vision, decreased libido, etc.;
• Persistent delays across multiple menstrual cycles;
• Excessive menstrual flow, prolonged periods, irregular cycles, etc.

What tests are needed for a delayed period?

• Ultrasound: Examines uterine development and endometrial condition; assesses ovarian size, follicle count, and size to aid diagnosis.
• Hormone testing: Fasting blood draw from the elbow vein on days 2–4 of the menstrual cycle (or the third day after withdrawal bleeding for amenorrhea patients) to measure estrogen, FSH, LH, testosterone, prolactin, progesterone, etc., determining if hormonal imbalance causes the delay.
• Thyroid function test: Checks for thyroid abnormalities that may lead to delayed periods.
• Complete blood count (CBC): Evaluates hemoglobin levels to detect anemia and support diagnosis.
• Gynecological examination: Includes vaginal discharge tests to rule out gynecological conditions causing the delay.

POTENTIAL DISEASES

What are the possible causes of delayed menstruation?

• Pregnancy: If the patient has had unprotected sexual intercourse recently and menstruation is delayed for more than 10 days, a pregnancy test can be purchased for self-testing or a hospital visit for a pregnancy test. A positive result indicates a high likelihood of pregnancy.
• Long-term use of certain medications: Drugs containing progesterone (such as progesterone, emergency contraceptives, etc.) and antipsychotic medications (such as risperidone, etc.) can easily cause hormonal imbalances^[2], leading to delayed menstruation.
• Endocrine disorders: Obesity, excessive dieting, staying up late, and irregular lifestyle habits can all cause endocrine disorders, resulting in delayed menstruation.
• Ovarian diseases: Conditions such as premature ovarian failure and polycystic ovary syndrome can lead to abnormal endocrine hormone levels, causing delayed menstruation.
• Other endocrine diseases: Hypothyroidism, hyperprolactinemia, and similar conditions can also cause endocrine disorders, leading to delayed menstruation.
• Chronic diseases: Patients with chronic hepatitis, tuberculosis, malignant tumors, severe iron-deficiency anemia, or aplastic anemia may experience delayed menstruation.
• Psychological factors: Stress, high work pressure, or environmental changes may also cause delayed menstruation.
• Uterine abnormalities: Uterine or cervical adhesions caused by procedures such as abortion or curettage can lead to delayed menstruation.