UPBEAT: how does obesity affect iron levels during pregnancy?

Professor Lucilla Poston, Mr Paul Seed, Ms. Angela Flynn, the UPBEAT Consortium

Researchers supported by Tommy’s have found a link between obesity, inflammation and iron levels which may be related to pregnancy complications.

Iron is important during pregnancy to support the healthy growth of the baby. Pregnant women need more iron than normal: enough for two people rather than one! This means that they are more likely not to get all the iron they need – they develop iron deficiency. The risk of this happening is higher for obese women, but the relationship between obesity and iron levels has not been studied much so far.  

We have shown that a small group of women who took part in the UPBEAT trial have a high level of a protein called CRP, or C-Reactive Protein, which plays a role in inflammation. Inflammation can affect the way that the body processes iron. If this goes wrong, then we can’t use iron to carry out the functions it needs to, like helping to transport oxygen in the blood. We think that inflammation during pregnancy in obese women leads to low levels of iron, which in turn may harm the baby.

Iron in the body is regulated by a hormone called hepcidin. The higher the level of hepcidin, the less iron is absorbed from our food into the blood, and the less iron will reach the placenta and the growing baby.

During normal pregnancy, less hepcidin is made so that the baby can get all the iron it needs. However, in obese women, inflammation is common and might lead to too much hepcidin being made. Evidence suggests that a substance that causes inflammation, interleukin 6 (IL-6), makes the body produce more hepcidin.

In the last 12 months, we have been exploring this relationship in 500 women (half obese and half of normal weight) to see if obesity, inflammation and iron deficiency are linked. We are currently measuring markers of inflammation in their blood such as Il-6 and CRP, as well as the women’s levels of hepcidin. All the women have been monitored for complications like premature birth, pre-eclampsia, diabetes, bleeding after birth and hospital stays to see if low iron levels are related to any of these problems.

We hope that the results of this work will help us find future ways of helping obese women to have healthy levels of iron. It will also inform health guidelines for when and how iron levels are screened during pregnancy, helping us find out early if mothers are at risk of iron deficiency.

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This study takes place in a Tommy's centre and is funded by Tommy's, the National Institute for Health Research, Guys and St Thomas' Charity, Chief Scientist Office Scotland, and the Allen Foundation

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