Early Period: Possible Causes and Risks

    Updated 17 October 2022 |
    Published 01 October 2018
    Fact Checked
    Reviewed by Dr. Anna Klepchukova, Intensive care medicine specialist, chief medical officer, Flo Health Inc., UK
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    Getting your period early can be an unpleasant surprise. There are many factors that can cause early menstruation. Today, we’ll tell you all about them and how you can control your body mechanisms a bit.

    Period a week early: is there anything to worry about?

    You've used Flo's period calculator to predict when your next period will arrive, but then: Surprise! You start bleeding days before it's expected. What's the deal?

    If your period comes early once in a while, it is likely normal and not a cause for concern. Menstruation might start early because of a change in your lifestyle, intense physical exercise, illness, or stress. However, sometimes it happens with no reason, and this is still not necessarily abnormal. So, if you get your period a week early, try not to worry. If your period is consistently irregular, you can let your health care provider know to rule out any problems.

    Discover our health assistant

    Discover what your irregular cycle could mean and what conditions it could be connected to with our Health Assistant.

    Early period causes

    Many people have irregular periods occasionally; others have them throughout their lives.

    Some possible causes of getting your period early: 

    • Hormonal imbalance 
    • Medical conditions
    • Taking certain medications 
    • Perimenopause
    • Over-exercising
    • Poor nutrition
    • Stress
    • Sudden weight gain or loss 

    Your birth control method can also affect your cycle. An emergency contraceptive pill can cause an early period. If you skip a few combined oral contraceptive pills, your hormone levels may drop, and bleeding may start before it’s due. If you have recently had an intrauterine device inserted, your body may react to it by bleeding.

    To avoid unpleasant surprises with your period coming early, it might be a good idea to have period products on hand, even if you’re not expecting your period. If you’re getting your period early for a prolonged period of time, make sure to ask your health care provider about it.

    Track your symptoms

    From hormonal phases of your cycle, irregular bleeding and spotting, Flo has you covered.


    Mayo Clinic Staff. “Menstrual Cycle: What’s Normal, What’s Not.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 13 June 2019, www.mayoclinic.org/healthy-lifestyle/womens-health/in-depth/menstrual-cycle/art-20047186?pg=2.

    Bull, Jonathan R, et al. “Real-World Menstrual Cycle Characteristics of More than 600,000 Menstrual Cycles.” NPJ Digital Medicine, Nature Publishing Group UK, 27 Aug. 2019, www.ncbi.nlm.nih.gov/pmc/articles/PMC6710244/.

    “Irregular Periods.” NHS Choices, NHS, 9 Apr. 2018, www.nhs.uk/conditions/irregular-periods/.

    History of updates

    Current version (17 October 2022)

    Reviewed by Dr. Anna Klepchukova, Intensive care medicine specialist, chief medical officer, Flo Health Inc., UK

    Published (01 October 2018)

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