What Can Affect Your Period

Certain factors can influence how consistent your menstrual cycle is

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Factors like pregnancy and breastfeeding cause changes in menstruation that you anticipate coming. But other things that can affect your period, such as medication use, certain health conditions, and stress, may cause changes that are less expected.

Knowing what can affect you period can help you know when a change may just be a natural part of life and when you need to contact your healthcare provider.

This article explains how life stages, health, and other issues affect your period.

calendar with period start date marked
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Life Stages and Menstruation

Your menstruating years can be broken down into stages. At each of these, your periods may change.


The onset of menstruation, which typically occurs sometime around 12 years of age, is called menarche.

During the first year or so of having your period, your body may still be getting into a routine. For example, you might have your first period and then not have another one for a few months.

Or, you might have a few periods and skip one a few months down the road.


Your period will likely settle into a regular cycle, but it may change with age and, of course, will be interrupted if you become pregnant or breastfeed.


Premenopause is a phase that you may enter some time in your 40s. At this stage of your life, your hormones may be shifting, but you won't necessarily see changes in your monthly cycles.


Perimenopause may begin in your late 40s. This is when your ovaries begin to produce less estrogen and progesterone. Fewer eggs are released and the production of monthly uterine lining declines.

Eventually, you will cease to release any uterine lining, which means your monthly periods will stop.


Menopause refers to the stage of your life in which you have stopped menstruating.

If you have not had a period for 12 months, you are considered to be in menopause.

Lifestyle Factors

Even while your body is establishing a normal pattern, or well after its developed a regular routine, other things that can affect your period.

Being Underweight

If your body has too little fat, you may experience amenorrhea, which is when you miss three or more periods in a row.

The loss of weight may be due to an unhealthy diet or excess exercise. Eating disorders also put you at high risk for menstrual irregularities and can cause other life-threatening problems.


Intense stress can also affect your period. Both physical and mental stress can cause problems with the production of the gonadotrophin-releasing hormone (GnRH), a hormone that regulates ovulation and menstruation.

If you are going through a particularly stressful time, your period may stop or change from its normal pattern. While this usually doesn't cause long-term period problems, try and reduce your stress if it is affecting your period.

If the stress is too much for you to handle on your own or continues for a long time, talk to a therapist or trusted friend or family member.


Medications are a common cause of irregular periods. Some examples of medications that can affect your period include:

  • Antipsychotics
  • Antidepressants
  • Weight loss medications
  • Steroids
  • Hormones
  • ADHD medications

If you’re taking one of these medications and begin to experience irregular periods, talk with your healthcare provider. They may be able to adjust your dose or switch you to a different medication.

Health Conditions

Physical illness can also affect your period. A bad cold or flu may be enough to throw your period off that month. Likewise, a major illness can certainly cause you to skip your period.

Make sure you alert your healthcare provider if your period is consistently irregular.

Chronic medical conditions can also affect your period. Hypothyroidism, or an underactive thyroid, can make your period irregular, with cycles being heavier and less frequent.

Other conditions that put stress on your body over a long period of time can also cause your period to fluctuate.

You might want to talk with your healthcare provider about a condition called a bleeding disorder if you have heavy menstrual periods or have ever had problems with the following:

  • Easy bruising
  • Frequent or prolonged nosebleeds
  • Prolonged or heavy bleeding after minor cuts, dental work, childbirth, or surgery

Pregnancy Loss

Bleeding after you have a confirmed pregnancy may be a sign of an ectopic pregnancy, or you may be miscarrying.

If you have had a positive pregnancy test or have reason to believe you're pregnant and you start bleeding, contact your healthcare provider. If you experience pain or significant blood loss, seek emergency help.

The most common bleeding disorder in girls and women (von Willebrand disease) runs in families, so your mother, sister, female cousins, or aunts also might have some of the signs listed above.

Other conditions that can affect your period include:

  • Uterine fibroids: Noncancerous tumors that occur within the uterus and cause heavy periods
  • Endometriosis: A reproductive condition where tissue similar to the lining of the uterus is found outside of the uterus, causing heavy, painful, or irregular periods
  • Polycystic ovarian syndrome: A disorder in which multiple cysts appear on the ovaries and cause irregular periods with some women only menstruating several times per year
9 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. U.S. Department of Health and Human Services: Office on Women's Health. GirlsHealth.gov. Getting your period.

  2. U.S. Department of Health and Human Services: Office on Women's Health. Menopause.

  3. National Institute on Aging. What is menopause?

  4. Huhmann K. Menses requires energy: a review of how disordered eating, excessive exercise, and high stress lead to menstrual irregularitiesClinical Therapeutics. 2020;42(3):401-407. doi: 10.1016/j.clinthera.2020.01.016

  5. Bae J, Park S, Kwon JW. Factors associated with menstrual cycle irregularity and menopauseBMC Womens Health. 2018 Feb;18(1):36. doi:10.1186/s12905-018-0528-x

  6. Yum SK, Yum SY, Kim T. The problem of medicating women like the men: conceptual discussion of menstrual cycle-dependent psychopharmacology. Transl Clin Pharmacol. 2019;27(4):127. doi:10.12793%2Ftcp.2019.27.4.127

  7. U.S. Department of Health and Human Service: Office on Women's Health. Period problems.

  8. American College of Obstetricians and Gynecologists. Ectopic Pregnancy.

  9. U.S. Department of Health and Human Services: Office on Women's Health. Bleeding Disorders.

By Tracee Cornforth
Tracee Cornforth is a freelance writer who covers menstruation, menstrual disorders, and other women's health issues.