Heavy menstrual periods, also known as menorrhagia, can deplete your iron stores. Iron is an important component of hemoglobin, the protein in red blood cells responsible for transporting oxygen to tissues. Further depletion of your iron stores can lead to iron-deficiency anemia. Keep reading to learn more about abnormal menstrual bleeding and how to prevent or manage iron deficiency. 

Heavy periods and Iron Deficiency

What is Menorrhagia?

Menorrhagia is a type of abnormal uterine bleeding (AUB) characterized by abnormally heavy or prolonged periods. Although women may experience a heavy menstrual period from time to time, it is not normal to experience severe blood loss due to menorrhagia.

Other types of abnormal uterine bleeding include:¹

• Bleeding between periods (intermenstrual bleeding or metrorrhagia)
• Periods at irregular intervals (metrorrhagia)
• Absence of period (amenorrhea)
• Too frequent periods (polymenorrhea)
• Irregular and heavy menstrual periods (menometrorrhagia)
• Bleeding after menopause 

Women, on average, lose 35-50 ml (about 2 to 3 tablespoons) of blood during menstruation. If you are losing about 80 ml (more than 5 tablespoons) per cycle,² you may need to be evaluated for menorrhagia. 

See your gynecologist if you think your period is too heavy or if you’re experiencing any of these symptoms: ³

• A period that lasts eight days or longer
• Using more menstrual products (pads or tampons) than you normally would 
• Vaginal bleeding or spotting in between periods
• Passing large blood clots
• Your periods are less than 21 days apart (unless that is your normal cycle)
• Unexplained fatigue, weakness, or shortness of breath

What are the Causes of Heavy Menstrual Bleeding?

There are many reasons why your period might be heavier than normal and it is important to have an accurate diagnosis before getting treatment. An individual may have one or more identifiable factors that contribute to abnormal bleeding.⁴ 

In some cases, the causes are ‘functional’, where nothing is essentially wrong or the underlying cause cannot be readily identified, but there is an impairment in the normal functioning of the body. Functional menorrhagia is associated with obesity, high fat intake, stress, sedentary lifestyle, and imbalance in prostaglandin levels.⁵

Common causes of heavy periods:^5,6

• Uterine fibroids are benign tumors of the uterus that affect one in every five women over 30. Heavy bleeding during menstruation is a common symptom of some fibroids.
• Uterine polyps can cause either heavy menstrual bleeding or irregular periods. There is a possibility for uterine polyps to be cancerous. 
• Endometriosis causes normal endometrial cells to grow in incorrect places, such as the ovaries, fallopian tubes, or pelvic ligaments. These cells are still sensitive to hormones and may bleed during menstruation. 
• Adenomyosis, like endometriosis, causes cells to be displaced and grow in the wrong places (uterine wall). The hormone-sensitive tissue bleeds into the muscle layer, causing pain and heavy bleeding.
• Pelvic inflammatory disease (PID) is caused by an infection, which may or may not be transmitted sexually. Some patients may experience heavy bleeding accompanied by fever and pelvic pain. 
• Polycystic ovary syndrome (PCOS) disrupts the balance of hormones in the body, which results in the thickening of the uterine lining without shedding for months. So when you finally get your period, you may experience excessive bleeding. 

How do Heavy Periods Cause Iron Deficiency?

Heavy menstrual bleeding can increase your risk of iron deficiency and makes you susceptible to iron deficiency anemia. This type of anemia is associated with several symptoms, including pale skin, fatigue, weakness, dizziness, headaches, and shortness of breath.

When you lose blood during menstruation, you also lose the iron found in those red blood cells. If your dietary iron intake does not replace the iron you lose during your period, you may develop iron deficiency anemia.⁷

Stages of iron deficiency:

• Iron depletion: hemoglobin levels are normal but you only have a small amount of iron stored. This stage may not cause symptoms.
• Iron deficiency:  your iron stores and blood iron levels are very low. You may experience tiredness or weakness.
• Iron deficiency anemia: your red blood cells have low hemoglobin because of prolonged iron deficiency. Having low hemoglobin means your body is unable to deliver oxygen to the cells of your body including your brain. It also affects your immune system and you may become more vulnerable to infection. 

How is Iron Deficiency Treated?

The best way to treat iron deficiency is to increase iron intake through your diet. If you have a problem absorbing iron or you can’t meet the recommended daily intake from food, your doctor may prescribe iron supplements to build up your iron levels quickly. If your iron deficiency is caused by heavy periods, your doctor may give you hormonal birth control pills to manage excessive bleeding. 

Recommended daily iron intake:⁸

• Teen girls (14-18 years) –  15 mg
• Adult women (19-50 years) – 18 mg
• Pregnant women – 27 mg
• Breastfeeding women – 9 mg

It’s recommended to eat a variety of foods to replenish your iron stores. Foods that are rich in iron include lean meat, seafood, poultry, nuts, beans, and iron-fortified bread and cereals. Eating food high in vitamin C, such as tomatoes, strawberries, and citrus fruits, will help your body absorb more iron. 

If you are experiencing symptoms of iron deficiency such as fatigue, weakness, pale skin, shortness of breath or dizziness, make sure to check in with your healthcare provider, as they can recommend treatment options for you.

Sources:

1. Albers J, Hull SK, Wesley RM. Abnormal Uterine Bleeding. American Family Physician. 2013;69(8):1915-1926. https://www.aafp.org/afp/2004/0415/p1915.html.‌
2. Warrilow G, Kirkham C, Ismail KM, Wyatt K, Dimmock P, O’Brien S. Quantification of menstrual blood loss. The Obstetrician & Gynaecologist. 2004;6(2):88-92. doi:10.1576/toag.6.2.88.26983
3. Harvard Health Publishing. Heavy Menstrual Periods. Harvard Health. https://www.health.harvard.edu/decision_guide/heavy-menstrual-periods. Published June 2020. Accessed September 21, 2020.‌
4. Munro MG, Critchley HOD, Broder MS, Fraser IS. FIGO classification system (PALM-COEIN) for causes of abnormal uterine bleeding in nongravid women of reproductive age. International Journal of Gynecology & Obstetrics. 2011;113(1):3-13. doi:10.1016/j.ijgo.2010.11.011‌
5. Trickey R, Trickey Enterprises. Women, Hormones & the Menstrual Cycle. Fairfield, Vic.: Melbourne Holistic Health Group; 2011.‌
6. Rees M, Hope S, Ravnikar V. The Abnormal Menstrual Cycle. Crc Press; 2005.‌
7. Iron Deficiency – Adults. Vic.gov.au. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/iron-deficiency-adults. Published 2012.
8. Office of Dietary Supplements – Iron. Nih.gov. https://ods.od.nih.gov/factsheets/Iron-Consumer/. Published 2016.‌