Light Period: 10 Common Causes & What to Do

A light period refers to either decreased flow or decreased duration of a period. This is generally not a concerning finding, especially if a lighter period is noted during times of stress or periods of intense exercise. 

However, a light period that persists for a long time can also be a sign of a hormone-related condition, like polycystic ovarian disease. It can also be a sign of pregnancy. 

If you notice changes to your period, you should consult a gynecologist for assessment and treatment as necessary.

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Common causes

The most common causes of a light period include: 

1. Excess stress

During times of high stress, like prior to giving an important presentation or when grieving a family member, the body produces more cortisol and adrenaline. High cortisol levels can triggers the brain to interrupt estrogen and progesterone production, which are necessary to stimulate a period. High levels of stress hormones can lead to a lighter period. 

Once the stressful time resolves, the menstrual cycle becomes more regular and returns to normal. 

What to do: You are advised to participate in activities that help to relieve stress, like regular physical exercise or having a hobby, for example. In addition, you can consume relaxing teas, like chamomile, lemon balm or valerian tea. You should try not to worry about your light period, as this can add to your daily stress and delay resolution.  

2. Natural aging 

It is normal for menstrual flow to fluctuate over the course of a lifetime. For example, between the ages of 20 and 30, women may notice a lighter period, and have some cycles with just spotting. After this age, periods become more regular and slightly heavier. 

However, with the arrival of menopause, women will again notice a light period, and the menstrual flow will gradually reduce. This is related to a decrease in estrogen levels. 

What to do: This is a normal and expected finding that should not be concerning. You are encouraged to speak with your gynecologist if you have any doubts or are unsure.

3. Weight changes

Sudden fluctuations in weight (gains or losses) can affect the menstrual cycle‘s duration, regularity and flow. Women with a very low body weight may have less frequent periods. Other factors that affect periods include malnutrition, intense exercise or increased stress levels.

What to do: You should avoid radical diets and sudden weight changes. Instead, opt for a lifestyle and eating plan that allows the body to adapt over a longer period of time. Ideally, your diet should be healthy and balanced. 

4. Intense exercise

Women who exercise ver intensely will often present with a light period. This is usually related to factors such as increased physical stress, low body fat and reduced energy levels. 

What to do: Your exercise should be dosed out over a week to prevent negative health effects, like a lighter period. Athletes may have more difficulty structuring an exercise plan that suits their health needs, and therefore they should speak to a gynecologist if they notice changes to their period. 

5. Pregnancy

Women will stop having periods during pregnancy, as the baby develops in the uterus. Some women may notice some spotting in the first weeks of pregnancy, which can be confused for a light period. Learn more about bleeding during pregnancy, and what to expect. 

What to do: If you suspect you may be pregnant, you should purchase a urine pregnancy test from the pharmacy, or consult a gynecologist for a blood test to confirm or rule out pregnancy. 

6. Polycystic ovarian syndrome 

Another relatively common condition that may cause a light period is polycystic ovarian syndrome (PCOS). This condition is characterized by an imbalance in hormone levels that directly affect menstrual flow. Common symptoms of PCOS include hair loss, acne and easy weight gain. 

What to do: Women are advised to consult a gynecologist if they present with PCOS symptoms. The doctor may order an abdominal ultrasound and blood tests to confirm or rule out this disease. 

7. Hyperthyroidism

Although it is more rare, a light period can also be a sign of hyperthyroidism. This occurs because the body produces a higher amount of thyroid hormones than normal, which can boost metabolism. When this occurs, the body burns more energy and can lead to weight loss and constant anxiety, which can affect the menstrual cycle.

Learn more about symptoms that can appear with thyroid problems, and take our online symptoms quiz to assess your risk. 

What to do: Hyperthyroidism can be confirmed the blood tests ordered by a family doctor or endocrinologist, as well as an ultrasound. Typically, treatment includes prescription medication to correct thyroid hormone levels.

8. Hyperprolactinemia

High prolactin levels, or hyperprolactinemia, usually occurs due to stimulation of mammary glands during pregnancy, or due to female hormone changes from ovulation and menstruation. 

One of the main symptoms of hyperprolactinemia is changes to the menstrual cycle, such as irregular periods, lighter periods or no periods. 

What to do: Treatment depends on the underlying cause of high levels. The doctor may discontinue hormone replacement therapy if you are taking it, or surgically remove a tumor from the pituitary gland. 

9. Birth control use

Chronic birth control use can lead to endometrial hypertrophy (or a thick uterine wall). This can lead to a lighter period. 

What to do: A light period that lasts for more than 2 weeks should be assessed by a gynecologist so that treatment can be initiated as necessary. The doctor may recommend a change to birth control type or dose.  

10. Asherman’s syndrome 

Asherman’s syndrome is characterized by the presence of intrauterine scar tissue, usually from previous uterine procedures. Associated symptoms include pelvic pain, infertility, and changes to menstrual flow, like a light period or amenorrhea. 

What to do: Treatment for Asherman‘s syndrome involves the surgical removal of the scar tissue adheres to the uterine wall. The doctor may also prescribe estrogen therapy.

When to worry about a light period

Usually, a light period is not a sign of any health problems. However, you are advised to a see a doctor if your light period presents with any of the following: 

  • No period for over 3 cycles
  • Recurrent breakthrough bleeding between periods
  • Intense pain during periods.

Women who have always had a lighter menstrual flow should not be worried, as a “normal” baseline period may differ from woman to woman.