Fibroids and iron-deficiency anaemia: the exhaustion no one warned you about

Uterine fibroids — particularly submucosal fibroids growing into the uterine cavity and intramural fibroids embedded in the muscle wall — dramatically increase the surface area of endometrium that sheds each period. They also interfere with the uterus's ability to contract down and stop the bleed. The result is heavier, longer periods that quietly outpace the body's iron intake.

Iron is the raw material for haemoglobin, the oxygen-carrying protein inside red blood cells. Every millilitre of menstrual blood contains around 0.5 mg of iron. A normal period loses 30–40 ml of blood (roughly 15–20 mg of iron); fibroid periods can lose 80–200 ml or more, month after month. Dietary iron absorption tops out at about 1–2 mg per day, so the ledger runs into deficit within a few cycles.

First your ferritin (iron stores) falls. Then your transferrin saturation drops. Only later does haemoglobin fall enough to be labelled 'anaemia' on a routine blood test. This is why many women feel unwell for months or years with 'normal' haemoglobin — their stores are already empty.

Iron deficiency does not appear overnight — it progresses through three stages, and the earliest ones cause symptoms long before the diagnosis of anaemia is made:

• Stage 1 — Iron store depletion: Ferritin falls below 30 μg/L. Haemoglobin is still normal. Fatigue, hair shedding, restless legs and brain fog can already be present.
• Stage 2 — Iron-deficient erythropoiesis: Transferrin saturation drops below 20%. The bone marrow cannot make enough haemoglobin. Symptoms worsen; exercise tolerance falls.
• Stage 3 — Iron-deficiency anaemia: Haemoglobin falls below 120 g/L (women) or 130 g/L (men). Red blood cells become small (low MCV) and pale (low MCH). This is the stage most GPs pick up — but it is late.

Iron-deficiency anaemia is chronically under-recognised because its symptoms creep in slowly and overlap with modern life. Ask yourself honestly whether any of these apply:

• Deep fatigue not relieved by sleep — feeling exhausted before the day starts.
• Breathlessness climbing stairs or carrying shopping that never used to bother you.
• Heart palpitations, especially at night or after mild exertion.
• Pale skin, pale inner lower eyelids, or blue-ish sclerae (whites of the eyes).
• Headaches, poor concentration and 'brain fog' throughout the working day.
• Hair shedding — more strands in the brush, thinner ponytail circumference.
• Brittle, ridged or spoon-shaped nails (koilonychia).
• Restless legs at night or a strong urge to move the legs when trying to sleep.
• Pica — cravings for ice (pagophagia), chalk, clay or soil.
• Sore, smooth tongue (glossitis) or cracked corners of the mouth (angular cheilitis).

A single full blood count (FBC) is not enough. Haemoglobin is the last marker to fall, so a 'normal' FBC can miss significant iron depletion. The proper work-up for a woman with heavy periods and fatigue includes:

• Full blood count (FBC) — haemoglobin, mean cell volume (MCV), mean cell haemoglobin (MCH). MCV under 80 fL points strongly to iron deficiency.
• Ferritin — the single most useful marker of iron stores. Anything under 30 μg/L is deficient; under 15 μg/L is severe. Values 30–50 μg/L in a symptomatic woman still warrant treatment.
• Transferrin saturation — under 20% is diagnostic of iron-deficient erythropoiesis.
• CRP — ferritin is an acute-phase reactant and rises with inflammation, so a raised CRP alongside a 'normal' ferritin can hide true deficiency.
• Vitamin B12 and folate — heavy bleeders can also become deficient in these, and mixed deficiencies are common.
• Coeliac screen (tissue transglutaminase antibodies) — considered when iron deficiency does not respond to treatment, to rule out malabsorption.

Replacing iron is only half the answer, but it is the half that makes you feel human again quickly. Options depend on how deficient you are, how well you tolerate oral iron, and how urgently you need to be surgery-ready.

Oral iron (ferrous sulphate, ferrous fumarate or newer formulations such as ferric maltol) is first-line for mild to moderate deficiency. Recent evidence supports alternate-day dosing rather than daily — it improves absorption and reduces gastrointestinal side effects. Ferritin should be rechecked at 8–12 weeks.

Intravenous iron (ferric carboxymaltose, ferric derisomaltose) is the game-changer for severe anaemia, poor oral tolerance, or when a woman needs to be optimised before surgery quickly. A single infusion of 1000 mg can raise haemoglobin by 20–30 g/L within 3–4 weeks and refill ferritin stores completely.

Blood transfusion is reserved for severe symptomatic anaemia (haemoglobin below 70–80 g/L with cardiovascular symptoms) — it treats the immediate crisis but does nothing to restore iron stores, and modern practice is to pair any transfusion with IV iron.

Iron tablets or infusions without addressing the fibroids means you are refilling a leaking bucket. Every subsequent heavy period pulls ferritin back down within weeks. Definitive treatment falls into three categories:

• Medical: tranexamic acid during periods (reduces flow by 30–50%), the levonorgestrel intrauterine system (Mirena — often stops bleeding within 6 months if fibroids are not distorting the cavity), and short courses of GnRH analogues to shrink fibroids pre-operatively.
• Minimally invasive surgery: hysteroscopic myomectomy for submucosal fibroids (through the vagina, no abdominal cuts), laparoscopic or robotic myomectomy for intramural and subserosal fibroids while preserving the uterus.
• Definitive surgery: open myomectomy for very large or multiple fibroids when uterine preservation is important, or hysterectomy when family is complete and other options have failed.
• Non-surgical alternatives: uterine artery embolisation (UAE) and radiofrequency ablation reduce fibroid volume by 30–50% and cut bleeding significantly — a good option when surgery is not desired and fertility is not a priority.

Going into fibroid surgery already anaemic doubles the risk of needing a blood transfusion, slows recovery, and worsens fatigue for months afterwards. Modern enhanced recovery pathways insist on treating anaemia before any planned uterine surgery — ideally getting haemoglobin above 120 g/L and ferritin above 100 μg/L.

For most women this means 4–6 weeks of oral iron with tranexamic acid to control bleeding, or a single IV iron infusion 2–4 weeks before surgery. The difference on the operating table and during the first two weeks of recovery is dramatic.

You do not need to prove your symptoms are 'bad enough' to seek help. Any of the following should trigger a same-week appointment:

• Heavy periods needing pad and tampon together, or flooding through clothing.
• Fatigue that is affecting your ability to work, exercise or care for children.
• Breathlessness or palpitations on light activity.
• Haemoglobin under 100 g/L, or ferritin under 15 μg/L on a recent blood test.
• Symptoms that returned after a previous course of iron tablets — the underlying cause was never fixed.