Why Is My Period Lighter Than Usual? 6 Common Reasons

A lighter period is not usually a cause for concern, but it can sometimes be a sign of hormonal shifts or certain medical conditions. Most people experience a natural fluctuation in their menstrual periods from time to time, and it can happen with stress, weight loss or gain, or changes in birth control.

It can also be a sign of pregnancy. Spotting in early pregnancy is often caused by implantation bleeding, which may just seem like a light period.

Lighter than normal period blood can be pink, red, or brownish. It may or may not involve cramps and period pain.

This article explores the different reasons why your period may be lighter than usual. It also explains common causes for lighter periods and when to call a gynecologist.

causes of a lighter period
Verywell / Brianna Gilmartin


Pregnancy is the most likely cause of a change in menstrual cycles for those who are sexually active. Some people may experience spotting or breakthrough bleeding in early pregnancy.

Implantation bleeding is often mistaken for a light period. Implantation is when a fertilized egg attaches to the uterine wall.

Implantation bleeding:

  • Occurs a few days before your period would normally appear
  • Can vary in shade from light pinkish-red to bright red or a reddish-brown to dark brown
  • May or may not be accompanied by cramps or pain
  • Does not always occur or may not be noticeable

Cervical bleeding is another potential cause of light bleeding during pregnancy. During pregnancy, the cervix is more sensitive and may bleed after intercourse.

If you know you are pregnant, talk to an ob/gyn or midwife about any vaginal bleeding. Light spotting with pink or brown blood can be normal throughout pregnancy. Heavier bleeding, bright red or dark blood, and blood accompanied by cramping or pain can indicate a problem and should be seen promptly.

If you suspect that you're pregnant pregnancy due to a lighter-than-normal period, take a pregnancy test, especially if you have not been using birth control. If you test negative, you can wait a week and test again or wait to see if your period comes next month.

If you had a lighter-than-normal period, make a note of it. Pregnancies are dated by the last menstrual period. Mistaking implantation bleeding for a light period alters the expected due date and may mean you are further along than you thought. The wrong date can shift some tests and other parts of your prenatal care.

Weight Loss or Gain

If you have suddenly gained or lost a lot of weight, you may see a change in your menstrual cycle. If you're underweight, the loss in fat can cause you to stop ovulating or releasing an egg every month. Exercising too much can also affect your periods because it changes the hormone levels in your body.


Emotional stress, such as the loss of a loved one, or major life stressors in work or your home life can take a toll on your body and affect your menstrual cycle.

Birth Control

Going on hormonal birth control can also cause a change in your period. It is not uncommon for people to experience lighter-than-usual periods and shorter periods while on a birth control pill or after getting a hormonal IUD, such as Mirena.

If a change in your period bothers you, you can use a birth control method that closely mimics your normal periods. Hormone-free options that should not or are less likely to affect your periods are also available, including internal and external condoms, a non-hormonal IUD device, and spermicidal foams.

Be sure to ask a midwife or doctor for advice on the method that is best for you.


If you are getting older, your periods may change, in some cases becoming lighter. This could mean that you are pre-menopausal. This does not necessarily mean you are no longer fertile, just that you are less likely to get pregnant. If you do not want to get pregnant, you should still use birth control until menopause.

Medical Conditions

There are medical conditions, such as cervical stenosis or Asherman's syndrome, that may cause a lighter flow than expected, though cramping may still occur. Both are uncommon, but these conditions can cause menstrual blood to get trapped in the uterus.

Asherman's syndrome is most often caused by uterine scarring following a dilation and curettage procedure (D&C), in which tissues from the uterus are removed.

Consult with your doctor if you have a lighter period than normal but are still having intense cramps.


Your period can be lighter than normal due to natural reasons, such as stress or perimenopause. It can also be lighter because of the birth control you are using, particularly if you are taking hormonal birth control pills or using a hormonal IUD. If your period seems off and you're not sure why, let a doctor know.

A Word From Verywell

Even if your periods seem consistent, it's a good idea to take note of your period each month—how heavy it is, what period symptoms you are having, and how many days your period lasts. Consider downloading a period tracker app on your smartphone, or simply taking notes about your period in your calendar. This way, if something is unusual about your period one month, you'll be more likely to notice.

Frequently Asked Questions

  • Can you have a period while pregnant?

    No, but some people have breakthrough bleeding that appears like a light period. Early pregnancy bleeding is very common and can appear like a light period. This is why some people do not always realize they are pregnant.

    However, if you know you are pregnant and experience any bleeding, contact your ob/gyn or midwife for guidance. While most breakthrough bleeding in pregnancy is nothing to worry about, bleeding can also signify a more serious issue.

  • Why is my menstrual cycle getting shorter?

    Aging is one reason for a shortened menstrual cycle. Starting in their 40s, some people can experience an irregular menstrual cycle that is shorter or longer than usual. It is also possible for a period to go away for a few months and then reappear. If you are at all worried about your menstrual cycle, contact your healthcare provider.

  • Can you make your period lighter?

    Yes, it is possible to make your period lighter. Regular exercise causes hormonal changes to occur which may result in a lighter period. Weight loss that accompanies exercise can also lead to a lighter period. In some cases, intense exercise performed regularly may even stop periods from happening. However, the opposite is also a possibility—intense exercise can result in bleeding that happens while you are not on your period.

  • What is considered a light period flow?

    What is considered a light period flow will differ from one person to another. That said, on average there are about two or three tablespoons of blood lost by a person on their period. Some people may have lighter periods than the average, while others can have heavier periods. This can also change from one month to the next.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Office on Women's Health. Underweight.

  2. Nelson AL, Massoudi N. New developments in intrauterine device use: focus on the US. Open Access J Contracept. 2016;7(1):127-141. doi:10.2147/OAJC.S85755

  3. The American College of Obstetricians and Gynecologists. Bleeding During Pregnancy.

  4. U.S. Department of Health & Human Services. Office on Women's Health. Your Menstrual Cycle.

By Robin Elise Weiss, PhD, MPH
Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor.