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More than 80% of pregnant women in Ireland are iron deficient by their third trimester, according to a new study my colleagues and I conducted. What we found particularly surprising was that the women were in otherwise good health.
Working alongside the University of Minnesota and the Masonic Institute of the Developing Brain, we analysed data from 641 participants based in the Republic of Ireland. All were pregnant with their first child. We took blood samples at 15, 20 and 33 weeks to track their iron levels.
Our study, one of the largest of its kind globally, reveals how widespread iron deficiency is, even in wealthy countries like Ireland. Indeed, the women in this study had higher rates of iron deficiency than women in some low-income countries where access to good healthcare and nutritious foods is more limited.
In the early months of pregnancy, 20% of women were iron deficient at 15 weeks, but none were anaemic. But by the third trimester, more than 80% were iron deficient. This suggests that while many women may begin pregnancy with normal iron levels, they are not getting enough to keep up with the body’s increasing needs as pregnancy progresses.
One of the most surprising aspects of this study is that about 75% of the women were taking iron supplements that met the European recommended dietary allowance of 15-17mg of iron. While this supplement was protective for some women, iron deficiency was still extremely common by the third trimester.
Why iron is so important
Pregnant women require ten times more iron during pregnancy to support their own needs and those of their growing baby. It’s used by both mother and baby to move oxygen around the body, which is essential for keeping all the cells and organs working properly.
Low iron levels are associated with a higher risk of harm for both mother and child.
Iron deficiency can have long-term consequences on the child’s brain development, leading to poorer cognition, behavioural problems and poorer motor skills. My previous research has shown that iron deficiency in early life is associated with behavioural problems at five years of age.
Our research suggests that women should be routinely screened for iron deficiency in early pregnancy. Currently, screening for the early stages of iron deficiency isn’t the norm in Ireland or many other countries, meaning many women don’t realise they have low iron levels until late in pregnancy — or not at all.
Screening in early pregnancy could identify those at the greatest risk of deficiency, allowing them to get help before it becomes a problem.
As well as screening, there’s a need to educate women about the importance of iron during pregnancy. Women are urged to focus on an iron-rich diet, including red meat, green leafy vegetables, beans, nuts and dried fruit. While iron from animal foods is more easily absorbed, iron-rich food from both animals and plants is important.
Routine screening and better education on the importance of iron during pregnancy are vital in benefiting families and helping avoid any unnecessary risks.
Elaine McCarthy has received research funding from the Health Research Board of Ireland and Enterprise Ireland. This research was funded through the European Union FP7 Framework and supported by the Health Research Board.
