Intravenous (IV) iron infusion

Introduction

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

Why might you need an IV iron infusion?

Giving iron directly into a vein is a way to increase the body’s iron levels quickly. It’s a more immediate treatment than tablets or dietary changes. The body needs iron to make haemoglobin (Hb), which is in red blood cells and circulates in the bloodstream.

Haemoglobin carries oxygen from the lungs to the rest of the body. 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 known as ‘iron deficiency anaemia’, and it can cause complications in pregnancy and after birth including stillbirth, prematurity, low birth weight and iron deficiency in your baby.

IV iron can be given directly into the vein via a cannula (a tube that is inserted into your vein). IV iron is indicated for the treatment of iron deficiency in the following conditions:

• When oral iron preparations are ineffective or cannot be used.
• Where there is a need to try to quickly increase the iron stores and haemoglobin.

The diagnosis of iron deficiency is based on laboratory tests. In pregnancy, it is most often used in the third trimester (after 28 weeks) because of the need to deliver iron rapidly to iron stores and raise haemoglobin prior to your baby being born. Its use may be considered following birth for those with oral iron intolerance.

Risks and side effects

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

• Nausea and injection site reactions are considered common (≥1% to <10%) and include redness, swelling, burning, pain, bruising, discolouration and/or irritation at the site of injection.
• Delayed reactions may also occur with iron that is given straight into the vein, these can be severe. They are characterised by arthralgia (joint paint) myalgia (muscle pain) and sometimes fever. The onset varies from several hours up to four days after administration. Symptoms usually last two to four days and settle spontaneously (almost without noticing) or following the use of simple pain relief such as paracetamol.
• On rare occasions skin staining can occur from the IV iron infusion. This can be significant and permanent. If you experience any discomfort during the infusion, it is important that you tell the midwife immediately.

Should you feel unwell in the days or week after the infusion, you should see your doctor or contact your midwife. A blood test may be needed to check the phosphate level; sometimes oral phosphate tablets are needed to replace the phosphate. This situation is uncommon.

Acute, severe anaphylactic (‘allergic’) reactions are considered rare (between 1 in 1,000 and 1 in 10,000 patients).

How long does an iron infusion take?

An IV iron infusion can take around 30 minutes to one hour to complete depending on the amount of IV iron administered. IV iron is given by qualified staff; you will be monitored whilst it is given and for at least 30 minutes after it has been discontinued.

When you go home

If you are asked to continue taking an oral iron supplement after the IV iron infusion, it should not be started earlier than five days after the last iron infusion.

Contact and further information

If you have any questions, please ask the healthcare team who will be happy to discuss this with you.

For further useful information about anaemia please visit Tommy’s (opens in a new tab).

References

Ferris Derisomaltose 100mg/ml solution for injection/infusion. Summary of Product Characteristics (SPC) Date of revision 04/04/2023 and Patient Information Leaflet| Pharmacosmos UK Limited. Via electronic medicines compendium (emc)

Drug Safety Update September 2013 volume 7, issue 2: Intravenous iron and serious hypersensitivity reactions: new strengthened recommendations to manage and minimise risk. Drug Safety Update August 2013, Vol 7, issue 1:A1

Challenges in Iron Supplementation. Jan 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 Transfusion Alternatives.