This is Why You’re Having Heavy periods in your 40s

heavy periods in your 40s

Have your periods got heavier since being in your 40s?

Have they become so unpredictable now that you don’t know whether you’ll get spotting, flooding or some strange combination of both?

In perimenopause – with oestrogen on a rollercoaster and progesterone on the decline – the stage is set for heavy periods (sigh).

You see, in your 40s, oestrogen can rise to levels 2 or 3 times higher than EVER before at some points in the cycle (see diagram below). Then, add to this declining progesterone, resulting in oestrogen ‘dominant’ cycles, and you’ve got a heavier period. There are other contributing factors for heavy periods as well, which we’ll look at later on in this blog.

Diagram showing how oestrogen can spike to really high levels in perimenopause (see red dotted line and area circled in black)

Many people talk about perimenopause in terms of LOW oestrogen, however perimenopause STARTS with HIGH and fluctuating oestrogen and ENDS with LOW levels (menopause).

Oestrogen spikes and oestrogen dominant cycles

During a regular menstrual cycle, oestrogen rises and falls in a relatively consistent and gentle way and it is met with progesterone in the second half of the cycle.

In your 40s however, due to the change in brain to ovary communication of perimenopause, oestrogen fluctuates more erratically (and we will FEEL these highs and lows in various ways) and you don’t make progesterone as much as before, resulting in more cycles that are ‘dominated’ by oestrogen.

Oestrogen dominant cycles are one thing, but oestrogen dominant cycles PLUS erratic fluctuations of oestrogen, with levels spiking 2-3 times higher than ever before at times, adds a whole other layer.

Low progesterone and heavy periods

If you’ve read my previous work and blogs before, you’ll already know that ovulation is the ONLY way the body makes progesterone each month and progesterone protects against heavy periods.

In the first half of the menstrual cycle, the brain releases follicle stimulating hormone (FSH), which encourages the ovaries to release follicles (containing an egg) and oestrogen levels to rise. This creates a thickening of the womb (uterus) lining, making it a healthy and fluffy lining for the implantation and housing of a fertilised egg.

Once ovulation (the release of an egg) has occurred, the ovaries go on to produce lots of lovely progesterone, which shelters the uterine lining from further build up (thickening) by oestrogen.

BUT! If ovulation does not occur then no progesterone is made to balance out stimulating oestrogen. This situation is called ‘unopposed’ oestrogen or oestrogen ‘dominance’ because without progesterone, oestrogen dominates the entire cycle. A healthy menstrual cycle is once where ovulation has occurred and progesterone dominates in the second half. ‘Non-’ or ‘An-’ovulatory cycles are more common in perimenopause and more so the further you move through your 40s and the closer you get to menopause.


Without progesterone (due to ovulation not occurring), the result is an unusually thick womb lining and this excessive buildup of tissue means heavier flow, longer, more intense periods. When blood flow is heavy your body doesn’t have time to keep up with anticoagulant activity, resulting in clotting.

You CAN support progesterone production in perimenopause

Whilst perimenopause is a time when ovulation becomes harder to achieve, it’s by no means impossible or something we should just accept. There are things we can be doing daily to support the body to ovulate when it otherwise might not have.

Stress is a BIG reason for ovulation NOT occurring. This is because the brain picks up on ANY kind of stress – including our modern day chronic stressors such as money worries, emotional burdens, worries about loved ones, dysfunctional relationships, lack of joy, juggling too much etc. etc. – and DOESN’T tell your ovaries to release an egg.

Managing stress is VITAL in your 40s.

So, oestrogen dominant cycles are more likely in your 40s (because of low progesterone/not ovulating as often) PLUS oestrogen is on a rollercoaster with potential for some really high spikes. This situation sets the stage for heavier periods.

Let’s look at some other causes of heavy periods

1) High intake of hormone-disrupting chemicals

These are chemicals that look like oestrogen once inside the body, allowing them to take the place of real oestrogen inside the cells, causing hormone havoc and increasing your body’s total load of oestrogen.
Hormone-disrupting chemicals can be a big driver of PMS including heavy periods as well as growth of fibroids and cysts.
They are found in products that contain artificial chemicals such as plastics, body, face and hair care products, perfumes, household cleaning products, detergents, candles, plug-ins and air fresheners.

What can you do?

  • Filter your water (e.g. Brita jug filter or a Berkey).
  • Use glass, ceramic or stainless steel for cooking, heating, storing and drinking.
  • Switch to cleaner skincare brands such Green People, Antipodes, Sukin, Jason, Ren, Neal’s Yard, Tropic and others.
  • Switch to cleaner household cleaning and detergent brands such as Bio-D, Method, Attitude and others.

2) Iron deficiency

You probably already know that heavy periods can cause iron deficiency but did you know that iron deficiency can make your periods heavier? 

What can you do?

  • Get your iron checked with a serum (blood) test that looks at iron, total iron-binding capacity (TIBC) and ferritin. If you’re deficient, you can work to increase iron-rich (in the form of heme, not non-heme) foods and or take an iron supplement, to help lighten your periods. ‘Chelated’ iron is a gentle form of iron that won’t cause gut issues and constipation like other more common forms of iron supplements can.

3) Inefficient breakdown and clearance of used oestrogen

You need to properly metabolise your oestrogen – to break it down and eliminate it permanently– or it will build up in your blood and increase your body’s total load. In other words, you need to use it, then LOSE it!

This is a complex process happening (primarily in your liver) all day everyday. Once your liver has done the work of breaking it down safely and efficiently, it is sent to your kidneys and gut for permanent excretion from your body via urine and (daily) bowel movements.

What can you do?

  • Reduce and limit alcohol, as the liver prioritises alcohol detoxification over used oestrogen.
  • Support a healthy gut and ensure at least one healthy, fully-formed bowel per day.

4) Chronic inflammation

Which can be created by inflammatory foods, poor sleep, alcohol, stress and gut bacteria imbalances, infections or parasites.

This is a complex process happening (primarily in your liver) all day everyday. Once your liver has done the work of breaking it down safely and efficiently, it is sent to your kidneys and gut for permanent excretion from your body via urine and (daily) bowel movements.

What can you do?

  • Remove inflammatory foods such as processed seed oils like vegetable, sunflower and rapeseed oils and cooking sprays, processed foods (so called ‘healthy’ meat substitutes I’m looking at you), refined carbohydrates, sugar and alcohol and even cow’s dairy. Most cow’s dairy in the UK contains a protein, called A1 casein that once digested, produces a peptide called BCM-7 that in many people releases inflammatory chemicals such as mast cells. A mast cell is a type of white blood cell found in connective tissues throughout the body that activate histamine in the body. Histamine increases vascular permeability and local blood flow. Goat and sheep milk products are usually fine as they contain A2 instead of the inflammatory A1 casein.
  • Manage stress, support your sleep, reduce or avoid alcohol, optimise gut health.

5) Insulin Resistance / blood sugar dysregulation

Blood sugar imbalances and or diets high in refined carbohydrates and low in protein can eventually result in cells that are ‘resistant’ to the action of the hormone insulin. Insulin resistance leads to chronic inflammation which, as we’ve seen above, is a big block to ovulation. Click here to read my blog post on insulin resistance)

6) Under- or over- active thyroid

Get a comprehensive thyroid check (that includes T4, T3 + Reverse T3 and thyroid antibodies)

7) Endometriosis or adenomyosis

I hope this blog post has been informative and helpful for you. I hope you have been able to identify any of the areas in this blog that may apply to you and it’s given you a place to start. See you in my next post! xx

Hi, I'm Francesca

I’m a Registered Nutritional Therapist who helps womens in their 40s find vibrant health and vitality, and thrive through perimenopause and beyond.

With nearly 10 years of experience working with hundreds of people, I empower and support women to support their bodies and hormones for a smooth and happy ride in their 4os.

Through our work together, clients have improved their energy, their periods and cycles, their mood, sleep, brain fog and digestion, and learned how to better manage their weight.

I am here to help you get back to YOU so you can have a fantastic time in your 40s.

My signature nutrition and lifestyle coaching approach to supporting women with their health and wellbeing is refreshing, down-to-earth and realistic.

Download the Free Guide

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Learn more about my signature course – Thrive Through Perimenopause – to start taking care of your hormone health once and for all, for a MUCH smoother ride in your 40s and beyond!

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