Does Taking Iron Make Your Periods Heavier? Let’s Find Out!

Last updated 01.29.2024 | by Dr. Karen Pike | 7 Minutes Read

This article has been reviewed and fact checked by Dr. Karen Pike, a senior physician administrator and board-certified emergency room doctor actively working in northern California. Read more at our medical disclaimer page.

Did you know that women lose an average of 220 to 250 mg of iron during their period? Your monthly bleed is one of the leading causes of iron loss in the body. And so it’s no surprise that, as women, we have much higher iron requirements than men.

For this reason, many of us take a daily iron supplement to avoid iron deficiency. But there’s a common misconception that taking iron during your period can lead to heavy menstrual bleeding and blood loss. Thankfully, this is a myth. However, it’s important to understand the relationship between iron and periods, especially during perimenopause, when heavier periods can become more common.

During my own perimenopause, I began to experience heavy periods for the first time in my life. And although I didn’t realize it at the time, I was on a fast track to iron deficiency. This was only picked up during a routine blood test, and it explained why I’d been feeling increasingly fatigued and breathless.

Thankfully, I was able to fix the problem by ensuring I ate sufficient iron in my diet and supplementing with a daily iron tablet. And now that I’ve passed menopause and no longer have periods, the underlying cause has been removed, and my iron levels have naturally stabilized.

Are you experiencing heavy periods during perimenopause? Have you been supplementing with iron, or are you considering doing so?

In this post, I’ll explain everything you need to know about iron and the menstrual cycle, including iron absorption in the body, the causes of low iron, and how to ensure that you support your iron intake throughout perimenopause, menopause and beyond.

Does Taking Iron Make Your Period Heavier?

In short, no. Supplementing with iron does not increase your menstrual flow. However, your menstrual flow can affect your iron levels. Heavy periods are one of the leading causes of anemia, a condition that develops when the body lacks sufficient iron.

How Do Heavy Periods During Perimenopause Affect Iron Levels?

Heavy periods (also known as menorrhagia) are quite common. Around 1 in 5 American women suffer from the condition, and women in perimenopause are more likely to be affected.

During this phase of life, fluctuating levels of estrogen can cause an increase in your usual flow. As a result, you might find yourself losing more blood each month than ever before.

But it’s not just blood you lose during your period. You also lose hemoglobin, a protein found in red blood cells that transports oxygen from the lungs to the cells around the body. Around three-quarters of the body’s iron is stored in hemoglobin, so when hemoglobin levels fall, crucial iron reserves do, too.

Are My Periods Heavy?

Are My Periods Heavy

So, how do you know if you have menorrhagia or heavy periods?

Look out for the following symptoms:

  • Bleeding for seven days or more
  • Passing clots bigger than a quarter (1 inch)
  • Needing to change your pad or tampon once an hour or more
  • Needing to double up pads
  • Needing to wake up in the night to change your pad or tampon

If you notice any of the symptoms above, you may be experiencing heavy menstrual bleeding. This increases your risk of developing anemia.

Signs of anemia include:

What to do if Heavy Periods Are Causing Iron Deficiency Anemia?

If you’re experiencing heavy periods and you suspect you may have an iron deficiency or anemia, it’s important to visit your doctor as soon as possible. They can assess your iron levels through a simple blood test.

If you have low iron levels because of a heavy flow, iron supplementation can help to restore your iron reserves quickly and effectively. Your doctor will also advise you on how to include more iron in your diet.

To address the underlying cause (heavy periods), your doctor may suggest hormonal birth control, which can reduce your monthly flow.

Other Causes of Iron Deficiency in Menopausal Women

Other Causes of Iron Deficiency in Menopausal Women

Heavy periods are the most common cause of iron loss in perimenopausal women. However, there are several other causes and conditions which can lead to suboptimal levels of iron in the blood.

Sometimes, your body is unable to absorb the iron found in food. Reasons for poor iron absorption include:

  • Certain medications, such as non-steroidal anti-inflammatory drugs (NSAIDs).
  • Gastrointestinal disorders such as IBD (inflammatory bowel disease) and celiac disease.
  • Consuming only plant-based iron (also known as non-heme iron).
  • Eating excess calcium or consuming antacids.
  • Genetic conditions such as hereditary hemochromatosis or iron-refractory iron deficiency anemia.

Should I Take Iron During My Period?

If your iron levels are depleted due to menstruation, your doctor may advise you to boost your iron stores with a daily supplement.

Women who still have their periods need around 14.8mg of iron per day to maintain optimum health.

Women who have reached menopause and no longer experience periods may need almost half that amount, around 8.7mg per day.

Other Ways to Maintain Healthy Iron Levels During Perimenopause

Alongside supplementation, other factors can help to ensure that you are getting enough iron.

Consuming foods high in vitamin C enhances the absorption of iron. If you struggle to get enough of this vitamin through your diet, consider supplementing with vitamin C pills or powder.

Also, always choose a high-quality iron supplement and take it on an empty stomach, either 30 minutes before or after a meal. Active iron is easier for the body to absorb, so look out for brands that contain this form.


What are the side effects of taking iron supplements?

Iron supplements are generally well tolerated. However, some people find that they experience an upset stomach, particularly when taking iron on an empty stomach. Other common side effects include constipation, diarrhea, dark stools, and a metallic taste in the mouth. Always follow the dosage guidelines, and if you’re concerned about side effects, speak to your doctor.

How can I experience lighter periods during perimenopause?

If perimenopause is causing heavier menstrual periods, speak to your doctor. They may be able to prescribe a treatment plan, such as hormonal birth control, which can help to address the underlying cause of excess bleeding and reduce heavy flow.

How long should I take iron supplements for during my period?

Each individual’s iron requirements are different. If you have a deficiency, your doctor will likely ask you to supplement your iron levels for a pre-agreed amount of time. They will then recheck your levels with a follow-up blood test. In some cases, it may be recommended to continue taking iron supplements in the long term.
If iron deficiency is caused by periods, once you reach menopause, you will likely require less, if any, extra iron intake.


Iron is an essential nutrient in all phases of life, including during perimenopause. However, the common misconception that taking iron supplements can cause heavier periods is simply not true. That being said, your periods and iron levels are interlinked, and a heavier-than-usual flow can deplete your iron reserves.

Iron deficiency is fairly common throughout perimenopause. I myself suffered from this problem when my menstrual flow increased. But thankfully, my doctor detected the issue quickly, and with some dietary changes and supplementation, my symptoms were quickly resolved.

If you suspect you’re low on iron, visit your doctor as soon as possible. They will assess your symptoms and, if necessary, provide a treatment plan that works for you.


  • Dr. Karen Pike

    Dr. Pike is a senior physician administrator and board-certified emergency room doctor actively working in northern California. She received her undergraduate degree at Dartmouth College, where she graduated Phi Beta Kappa and played collegiate soccer. She attended Georgetown University for medical school and performed her residency in emergency medicine at Stanford University. She was part of the first-ever, women-majority emergency medicine program in United States. Dr. Pike is also the primary medical consultant for “Grey’s Anatomy,” a role she has held since the pilot episode when she partnered with Shonda Rhimes as the show’s original medical consultant. At her hospital, she was the second woman Chief of Staff. Today serves as the Director of the Emergency Department. Whether in leadership or direct patient care, her dedication to excellence in communication, quality, and collaboration is unwavering.