Irregular periods are characterized by menstrual cycles that last for a different amount of days each month. It an make it difficult to determine the fertile period and the best time of the month to get pregnant. An irregular period can be a normal finding, however, and can occur in adolescents who have started menstruating, or in women who are approaching menopause.

An irregular period can also be a sign of another underlying health condition, like an eating disorder, stress, excessive exercise, a gynecological diseases or abnormal hormone production.

If you consistently experience irregular periods, you should see your gynecologist for assessment and treatment as needed, especially if you plan to become pregnant.

Why is my period irregular?

Irregular periods can be caused by:

1. New periods or pre-menopause

Irregular periods are considered to be a normal finding in adolescents just starting their periods, and in women who are approaching menopause. During these times, hormone levels are expected to fluctuate more, which can impact your menstrual cycle and period flow.

What to do: Although an irregular period during these times of your life is expected, you are encouraged to see a gynecologist for assessment to rule out any other possible causes.

Women who are pre-menopausal may experience late periods with other symptoms, which can be managed with hormonal replacement therapy. Read more about common menopause symptoms and how they can be treated.

2. Birth control changes

Being on birth control is a practical way to maintain regular periods, as these medications keep hormone levels stable. However, changing your birth control type, changes in dosing, or forgetting to take it may lead to changes in hormone levels, which can cause irregular periods.

Stopping a birth control pill can trigger the ovaries to start producing hormones on its own, and until this process regulates itself, periods may be irregular.

What to do: Irregular periods due to changes in birth control are normal and do not require any specific interventions. With time, the body will usually adapt to contraceptive changes. However, irregular periods that present with other symptoms (like spotting or heavier bleeding with clots) should be assessed by your gynecologist.

3. Pregnancy and breastfeeding

Conception is associated with changes in hormone levels that occur with the objective of supporting fetal development. In a viable pregnancy, these changes persist in order to maintain pregnancy to term, leading to the absence of a period.

After childbirth, these hormones will start to stabilize to normal levels, but until then, periods may be irregular. Women who are breastfeeding will also produce prolactin, which which inhibits ovarian functioning and also cause an absence of or irregular periods.

What to do: These are expected findings that do not require any medical intervention.

4. Stress

Stress and anxiety, for example, can increase the production of hormones such as adrenaline and cortisol. These can directly impact the regularity of the menstrual cycle.

What to do: You should engage in activities every day that promote relxation and your mental health. Many people benefit from being outdoors, exercising regularly, drinking calming teas, and eating a diet that is high in tryptophan (which is an amino acid precursor to serotonin).

5. Excessive exercise

Excessive exercise, which is common in athletes, can lead to abnormal or the absence of periods. Intense physical activity leads to the production of hormones like endorphins or ACTH which interfere with the timing of your periods.

What to do: To regulate your period, you should reduce the intensity or frequency of your exercise. It is also important to consult a gynecologist to assess your hormone levels and rule out any other possible causes for irregular periods.

6. Hormonal conditions

Some hormonal conditions such as polycystic ovarian syndrome, hypothyroidism and hyperprolactinemia, for example, can impact your estrogen and progesterone levels and lead to irregular periods.

Depending on the condition, your late periods may be accompanied by other symptoms, like weight gain, difficulty losing weight, acne, difficulty getting pregnant and excessive fatigue.

What to do: It is important to consult a gynecologist so that symptoms can be assessed and blood and imaging tests can be carried out to help identify the cause of symptoms and irregular menstruation, and thus indicate the most appropriate treatment, which can involve the use of medications for hormone replacement and to regulate the menstrual cycle.

7. Eating disorders

Some eating disorders such as anorexia or bulimia can also cause irregular periods. This is related to malnutrition, which can lead to reduced hormone production in the ovaries in the body's attempt to conserve energy.

What to do: Irregular periods caused by eating disorders can resolve once the underlying condition is addressed. The doctor may advise a consultation with a psychologist and registered dietitian to improve your relationship with food and with your body image. The dietitian can help to develop a meal plan that meets your needs and goals.

8. Gynecological diseases

Gynecological diseases like endometriosis, fibroids, tumors or Asherman syndrome (which is associated with the formation of scar tissue in the uterus) are diseases that cause abnormalities in uterine tissue and can lead to irregular periods.

These conditions can also lead to the absence of a period.

What to do: It is important to consult a gynecologist if you suspect your may have a gynecological condition. The doctor may order testing, like bloodwork or an ultrasound, to help reach a diagnosis and help to guide treatment. Depending on the disease, he or she can prescribe hormonal medication to help regulate menstruation or advise surgery to remove fibroids or scar tissue.

9. Medication side effect

Medications like antidepressants and antipsychotics, for example, can impact your estrogen and progesterone levels, leading to irregular periods.

What to do: If you notice irregular periods after starting a new medication, it is important to inform your prescriber to determine whether it is related to a side effect. The doctor may consider prescribing a new dose or a new medication.