Intravenous (IV) iron infusion

This leaflet is for women and birthing people who have been recommended to have iron given by a drip into their vein (an intravenous infusion). It should help you understand IV iron infusions and the potential benefits.

Why do I need an IV iron infusion?

Your body needs iron to make haemoglobin (Hb), which is found in your red blood cells. These red blood cells circulate in your blood stream. Haemoglobin carries oxygen from your lungs to the rest of your body, including to your baby via your placenta.

Iron helps our muscles store and use oxygen. If your iron levels are low, you may feel tired and not able to carry out your normal routine. When the amount of iron in the body gets too low, the haemoglobin levels fall below normal. This is diagnosed based on laboratory tests and is known as ‘iron deficiency anaemia’. Complications of this in pregnancy and after birth; include stillbirth, premature birth, low birth weight, and iron deficiency in baby.

An iron transfusion may be recommended when:

• Iron tablets have not worked for you, or cannot be used.

• Where there is a need to try and quickly increase your iron stores and haemoglobin.

In pregnancy, it is most often used in the third trimester (after 28 weeks). Due to the need to deliver iron rapidly to iron stores and raise haemoglobin before your baby is born. It may also be used after childbirth for those with iron intolerance or low haemoglobin.

How will IV iron be given?

• Your vital signs (blood pressure, temperature, pulse, and oxygen levels) will be taken before you receive your iron infusion.

• Iron will be given directly into your vein, via a cannula (a small tube that is inserted into your vein). It will be given as a slow infusion usually over 30 minutes. It is a way to increase your body’s iron levels quickly. It is a more immediate treatment than tablets or changes to your diet.

• Your midwife will insert the cannula. If your veins are deep or not obvious, they may ask an anaesthetist to insert the cannula instead.

• Your vital signs will be taken again after the injection. You will be observed for 30 minutes to make sure you feel well.

What are the risks and side effects?

Intravenous iron infusions are considered safe in pregnancy. But like all medication it can have some unwanted side effects that include:

Common side effects up to one in 10 people

• Nausea (feeling sick)

• Injection site reactions including:

  • redness

  • swelling

  • burning

  • pain

  • bruising

  • discolouration and / or irritation at the site of the injection.

Uncommon side effects one in 100 people

• Headache

• Feeling tired

• Flushing, sweating, fever, feeling cold, shivering

• Fast heart rate, low blood pressure

• Muscle / joint pains

• Non-allergic reaction. Symptoms may include facial flushing, chest tightness, shortness of breath, and / or joint pains. This usually settles quickly if the injection is stopped and / or continued more slowly.

• Dizziness, blurred vision, altered sense of taste, numbness

• Tummy pain, vomiting, diarrhoea, or constipation

• Low or high blood pressure, or increased heart rate

• Itching or hives

• Low phosphate levels

• Liver enzymes increased.

Rare side effects one in 1000 people

• Irregular heart beat

• Hoarseness

• Seizure

• Tremor

• Altered mental status

• Flu-like illness.

Delayed reactions may also occur with iron that is given straight into the vein, these can be severe. These are: arthralgia (joint pain), myalgia (muscle pain), and sometimes fever. When this starts varies, from several hours after you are given the IV, to up to four days after. Symptoms usually last two to four days. They should settle naturally (almost without noticing), or following the use of simple painkillers such as paracetamol.

Skin staining can occur from the IV iron infusion. It will appear as a brown stain on the skin. This may be permanent, but may fade over time. This is due to the drug being administered into your skin, rather than into your bloodstream.

1. 
   Example of skin staining shortly after infusion
2. 
   Example of skin staining six months after infusion

Tell the midwife caring for you immediately if you notice or experience:

• Pain, swelling, a feeling of pressure, or a ‘tingling’ sensation at the injection site.

• Changes to the colour of your skin at the injection site.

This will minimise such risk.

• If you do feel unwell in the days or week after the infusion, see your GP or contact your midwife. A blood test may be needed to check your phosphate level and sometimes oral phosphate tablets are needed. This situation is uncommon.

• Acute severe anaphylactic (‘allergy’) reactions are considered rare. They happen to between one in 1000 and one in 10,000 patients.

How long does an iron infusion take, and what can I expect after?

• An IV iron infusion can take around 30 minutes to one hour to complete.

• IV iron is given by qualified staff.

• You will be monitored whilst it is given and for 30 minutes after the infusion has finished.

• You may need one or two infusions spaced one week apart.

• Following your iron infusion, you are able to restart any oral iron tablets five days after your last infusion. 

• You will need to have a blood test to check your iron levels two to six weeks after your infusion.

What happens when I go home?

You will be advised to continue taking oral iron supplements after your infusion. You should not start taking these any earlier than five days after the last infusion.

What are the alternatives?

If you would like to discuss the alternatives to having an iron infusion, you can discuss the option of having a blood transfusion.

What if I have any questions or concerns?

If after reading this information you have further questions or concerns, please speak to your midwife or obstetrician.

Further information 

• Tommy's: Anaemia and pregnancy

References

• Parmocosmos UK Limited (2020). Monofer 100mg/ml solution for injection/infusion. Summary of Product Characteristics (SPC) Date of revision 26/05/20 and Patient Information Leaflet. Available via Electronic Medicines Compendium web site.

• Drug Safety Update (2013). Intravenous iron and serious hypersensitivity reactions new strengthened recommendations to manage and minimise risk. Drug Safety Update September 2013 (7)2. Issue 1:A1

• Challenges in Iron Supplementation. January 2005. Action. News from the anaemia care and treatment group. April 2007. Summary of discussions from a meeting held during the 8th Annual Meeting of the Network for Advancement of Transfusions Alternatives.