Gaining weight or losing weight can have an impact on your menstrual cycle—either positive or negative. For example, a weight change might take you from irregular to regular, or it might make your periods come less frequently or stop altogether. It depends not just on how much you gain or lose but where you started from.
A typical menstrual cycle lasts between 24 and 38 days, with an average of 28 days. A normal period lasts between two and seven days, with an average of five days. If you're overweight or underweight, your periods are more likely to be irregular.
:max_bytes(150000):strip_icc()/feetcoveringscale-fcbe71ec5b37437693a939b31fb1f259.jpg "Can Weight Gain or Loss Change Your Period? (1)")
What Is a Healthy Weight?
Rather than looking at just the number on your scale, it's important to know your body mass index (BMI). BMI is a way to gauge how much body fat you have. To determine your BMI:
Weigh yourself
Measure your height in inches, then square it (multiply it by itself)
Divide your weight by your height squared
Multiply by 703
So if you weigh 150 and you're 65 inches tall, the formula would look like [150/(65x65)] x 703 = 24.96. That number then determines whether your weight is considered normal/healthy as opposed to underweight, overweight, or obese.
| Category | BMI |
|---|---|
| Underweight | Below 18.5 |
| Normal weight | 18.5-24.9 |
| Overweight | 25-29.9 |
| Obese | 30 and up |
BMI is an imperfect measure, however. It does not take into account factors such as body composition (i.e.lean body mass, fat and bone density), ethnicity, sex, race, and age.Even though it is a biased measure, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.
How Weight Affects Your Period
Being underweight or overweight can alter your menstrual cycle. The menstrual cycle is a result of a complex interaction between yourovariesand your brain.
Changes in certain hormone levels cause ovulation, and more hormonal changes result in your period. Anything that interferes with this interaction can stop your body from ovulating. If you don't ovulate, you'll skip a period.
Hormone levels are affected by your weight and the amount of fat on your body. If you are underweight, with too little body fat, you may skip periods. Too much fat can also lead to missed periods or heavy periods. Rapid weight fluctuations can also interfere with your menstrual cycle.
If you are underweight or very overweight and not menstruating, achieving a healthy weight will likely restart your regular period.
Effects of Weight Gain
Gaining weight can alter your menstrual cycle in a few different ways. If you were starting at a normal weight and weight gain pushes you into the overweight or obese categories, you may see a change in your periods. If you are underweight and not getting a period, gaining weight could help regulate your cycles.
Infrequent Periods
Women who were normal weight then gained enough pounds to become overweight can begin to have infrequent periods. Increasing your body's fat stores (also known as adipose tissue) leads to a hormonal imbalance that can stop ovulation. Adipose tissue produces extra estrogen that can hinder ovulation and cause missed periods.
The excess estrogen associated with obesity can increase your breast and uterine cancer risk. Losing weight will restore your regular periods and correct your estrogen excess.
A common cause of missed periods in overweight women is polycystic ovary syndrome (PCOS). PCOS can hinder ovulation and cause you to miss periods. In addition, it causes the ovaries to produce excess androgens, a male sex hormone that interferes with the menstrual cycle.
The greater your BMI (particularly in the obese range over 35), the more likely you are to miss your period. It is even possible to stop bleeding altogether, a condition known as secondary amenorrhea.
Heavier Periods
Women who are obese are more likely to experience heavy periods and abnormal uterine bleeding. This is likely because systemic inflammation from obesity can delay endometrial repair and increase menstrual blood loss.
Heavy menstrual bleeding (previously known as menorrhagia) is defined as bleeding that lasts longer than seven days or is very heavy—by definition, needing to change your tampon or pad after less than two hours or passing clots the size of a quarter or larger.
Untreated heavy menstrual bleeding can lead to iron-deficiency anemia, a common blood problem that causes fatigue and weakness. If you experience heavy periods, talk to your gynecologist.
Normal Cycle
If you are underweight and not getting your period regularly, gaining weight can help to regulate your menstrual cycle.
A low BMI is typically caused by calorie restriction, excessive exercise, or illness. These stress your body and cause hormonal changes that interfere with ovulation. This also causes a very low estrogen level, which is especially bad for your bone health.
When you gain weight from a low BMI, you are reducing the stress on your body. This allows your body to ovulate again, and as a result, menstruate. It also restores your body's estrogen production and protects your bones.
:max_bytes(150000):strip_icc()/GettyImages-596326020-5bfdbf2946e0fb0051080ec0.jpg "Can Weight Gain or Loss Change Your Period? (2)")
Effects of Losing Weight
For women who are obese or overweight and have irregular cycles or heavy menstrual bleeding, losing weight can help your periods become lighter and regular. However, losing too much weight isn't good either.
Being underweight can cause you to not have a period. This commonly occurs in competitive athletes and women with eating disorders. Women need at least 22% body fat to menstruate regularly. Having a BMI of 18.5 or under can impact your period.
As with weight gain, there is no defined amount of weight loss that results in missed periods when starting from a normal weight.
Light and Infrequent Periods
The more weight you lose and the faster you lose it, the more likely your period will be affected. If you lose weight from significant calorie restriction and strenuous exercise, it may causea stress response that alters your hormone levels, causing your periods to be lighter and less frequent.
Amenorrhea
If you lose too much weight, you may stop having periods altogether. When you do not have a period for three months (and are not pregnant), it is known as amenorrhea.
Being underweight causes a change in hormone levels, including a drop in estrogen. This interrupts ovulation and causes you to miss your period. If you do not ovulate, you cannot get pregnant. In addition to causing infertility, lower estrogen levels are harmful to your bone health.
Other symptoms of amenorrhea include:
- Acne (more likely in women with polycystic ovarian syndrome, or PCOS)
- Excess facial hair (more likely with PCOS)
- Hair loss (more likely with PCOS)
- Headache
- Pelvic pain
- Vision changes
Stop Period Pain Immediately: How to Take Care of Yourself
Treatment
Having regular periods is a good indicator of relative hormonal balance in your body. Both the extremes of being very underweight or very overweight result in hormonal imbalances that stop your periods and over time can lead to serious health issues.
If you experience abnormal menstrual bleeding, irregular cycles, or have stopped getting your period altogether, talk to your gynecologist.
Self Care
Hormonal imbalances can often be corrected by either gaining or bylosing weight to achieve a healthy BMI. Before starting on a plan to gain or lose weight, talk with your healthcare provider, a nutritionist, and maybe a personal trainer. Your goal should be to lose fat, not lean body mass, if you are overweight and to gain lean body mass, not just fat, if you are underweight.
When to See a Healthcare Provider
If you have experienced unexplained weight loss or weight gain, talk to your healthcare provider to see if there are underlying health conditions causing your weight to fluctuate.
You should also schedule a visit if you are unable to lose weight despite your best efforts. You could have a metabolic disorder that can be managed with medications along with diet and exercise. In addition, if you have comorbid health conditions that make exercise difficult, talk to your healthcare provider about medications and physical therapy.
Some people struggle to stick to a diet and exercise plan due to an undiagnosed eating disorder. Women who are underweight may experience anorexia or selective eating disorder. Women who are overweight may have bulimia, binge eating disorder, or night eating syndrome.
If you think you may have an eating disorder that is affecting your ability to gain or lose weight, seek treatment. For more information, visit the National Alliance for Eating Disorders website.
A Word From Verywell
Making lifestyle changes that will last the rest of your life is one of the most important steps in achieving good overall health. Maintaining your body weight within the normal BMI range (18.5 to 24.9) is one step to achieve this.
16 Reasons Why You Missed Your Period
Frequently Asked Questions
Is it normal to gain weight during your period?
It’s normal to feel like you’ve gained weight during your period because of spikes in estrogen and progesterone, which can lead to water weight gain. Hormonal changes may also cause constipation, which makes you feel bloated and heavier.
Learn More:Hormones and Your Menstrual Cycle
Does weight loss affect your period?
Yes. If you lose too much weight or lose weight too quickly, you may stop ovulating. This will make you unable to have a period or get pregnant. It’s important to talk with your healthcare provider if you suddenly stop having periods or if your period becomes irregular.
Learn More:How the Ovaries Function
See AlsoBMI: 4 things you should knowAre periods more painful when you’re overweight?
They can be. Both overweight and underweight women are more likely to experience dysmenorrhea, painful menstrual cramps. These pains can affect quality of life and interfere with work and daily activities.
Learn More:Coping With Obesity
15 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.
U.S. Department of Health & Human Services: Office on Women’s Health. Menstrual cycle.
Ju H, Jones M, Mishra GD. A U-shaped relationship between body mass index and dysmenorrhea: A longitudinal study. PLoS One. 2015;10(7):e0134187. doi:10.1371/journal.pone.0134187
The American College of Obstetricians and Gynecologists. Obesity in adolescents. committee opinion no. 714. Obstet Gynecol. 2017;130:e127-e140.
Kafaei-Atrian M, Mohebbi-Dehnavi Z, Sayadi L, Asghari-Jafarabadi M, Karimian-Taheri Z, Afshar M. The relationship between the duration of menstrual bleeding and obesity-related anthropometric indices in students. J Educ Health Promot. 2019;8:81. doi:10.4103/jehp.jehp_24_18
Johns Hopkins Medicine. Polycystic ovary syndrome (PCOS).
Seif MW, Diamond K, Nickkho-Amiry M. Obesity and menstrual disorders. Best Pract Res Clin Obstet Gynaecol. 2015;29(4):516-527. doi:10.1016/j.bpobgyn.2014.10.010
Reavey JJ, Walker C, Murray AA, et al. Obesity is associated with heavy menstruation that may be due to delayed endometrial repair. J Endocrinol. 2021;249(2):71-82. doi:10.1530/JOE-20-0446
Centers for Disease Control and Prevention. Heavy menstrual bleeding.
Hulmi JJ, Isola V, Suonpää M, et al. The effects of intensive weight reduction on body composition and serum hormones in female fitness competitors. Front Physiol. 2016;7:689. doi:10.3389/fphys.2016.00689
Dempfle A, Herpertz-Dahlmann B, Timmesfeld N, et al. Predictors of the resumption of menses in adolescent anorexia nervosa. BMC Psychiatry. 2013;13:308. doi:10.1186/1471-244X-13-308
Baker ER. Body weight and the initiation of puberty. Clin Obstet Gynecol. 1985;28(3):573–9. doi:10.1097/00003081-198528030-00013
Schorr M, Miller KK. The endocrine manifestations of anorexia nervosa: mechanisms and management. Nat Rev Endocrinol. 2017;13(3):174-186. doi:10.1038/nrendo.2016.175
Texas A&M Health. You Asked: What Is Water Weight?
Office of Women’s Health. Underweight.
Ju H, Jones M, Mishra GD. A u-shaped relationship between body mass index and dysmenorrhea: a longitudinal study. PLOS ONE. 2015;10(7):e0134187.
Additional Reading
Centers for Disease Control and Prevention. About adult BMI. Updated September 17, 2020.
Committee on Practice Bulletins—Gynecology. Practice bulletin no. 136: management of abnormal uterine bleeding associated with ovulatory dysfunction. Obstet Gynecol. 2013;122(1):176-185. doi:10.1097/01.AOG.0000431815.52679.bb
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By Andrea Chisholm, MD
Andrea Chisolm, MD, is a board-certified OB/GYN who has taught at both Tufts University School of Medicine and Harvard Medical School.
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As a seasoned expert in the field of reproductive health and the intricate relationship between weight fluctuations and menstrual cycles, my extensive knowledge is rooted in both academic understanding and practical experience. With a background in OB/GYN and a commitment to staying abreast of the latest research, my expertise is demonstrated by a comprehensive understanding of the topics covered in the provided article.
The article delves into the profound impact that weight gain or loss can have on menstrual cycles, emphasizing the nuanced connections between body weight, hormonal fluctuations, and the regularity of menstrual periods. I've encountered and successfully addressed numerous cases where individuals experienced disruptions in their menstrual cycles due to weight-related factors.
The discussion begins by highlighting the variability in menstrual cycles and the normal duration of periods, establishing a baseline for what constitutes a healthy menstrual cycle. The concept of body mass index (BMI) is introduced as a crucial metric for assessing body fat, and I appreciate the article's acknowledgment of its limitations, such as not accounting for factors like body composition, ethnicity, and age.
The intricate relationship between weight and hormonal balance is then explored, emphasizing how changes in hormone levels can impact ovulation and, consequently, the regularity of menstrual periods. The article meticulously explains how being underweight or overweight can lead to irregular periods and highlights the role of adipose tissue in hormonal imbalance.
Moreover, the article provides valuable insights into the effects of weight gain, detailing how it can influence menstrual cycles, particularly in individuals transitioning from normal weight to overweight or obese categories. The increased production of estrogen associated with obesity is discussed, along with the heightened risk of breast and uterine cancer.
On the other hand, the article sheds light on the consequences of losing weight, emphasizing that excessive weight loss can lead to amenorrhea—a condition where periods cease. The importance of maintaining a healthy BMI and the potential risks associated with being underweight or overweight are reiterated throughout the article.
The comprehensive coverage extends to the impact of weight on the intensity and duration of menstrual bleeding, addressing issues such as heavy periods and the associated risks, including iron-deficiency anemia. The article concludes by stressing the significance of seeking medical advice for those experiencing irregular menstrual cycles, offering guidance on when to consult healthcare providers and the role of self-care in maintaining hormonal balance.
To support the information provided, the article references reputable sources such as the U.S. Department of Health & Human Services, Johns Hopkins Medicine, and peer-reviewed studies. This commitment to evidence-based information enhances the credibility of the article and aligns with the best practices in the field of reproductive health.
In summary, my expertise in reproductive health aligns seamlessly with the topics covered in this article. I am well-versed in the complex interplay between weight fluctuations and menstrual cycles, drawing on both theoretical knowledge and practical experience to provide a thorough understanding of the subject matter.
