The Study
Iron deficiency predicts poor maternal thyroid status during pregnancy.
This study looked at a group of pregnant women and found that those with low iron also often had weird thyroid numbers. But it didn’t change anyone’s diet or give them pills — so we don’t know if low iron made the thyroid act up, or if something else caused both.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
When a pregnant woman doesn't have enough iron, her thyroid hormone levels can drop, making her feel tired and foggy—just like someone with an underactive thyroid.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes—this means low iron during pregnancy could mimic or worsen thyroid problems, which might affect the baby's brain development.
- 240% of pregnant women had low iron; 16% had low thyroid hormone (TT4).
- 3Those with low iron were 7.8 times more likely to have low thyroid hormone.
- 4Iron levels strongly predicted thyroid hormone levels.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of clinical endocrinology and metabolism
Year
2007
Authors
M. Zimmermann, Hans Burgi, R. Hurrell
Related Content
Claims (5)
Iron deficiency produces the same symptoms as an underactive thyroid, such as fatigue and brain fog, because iron is necessary for producing thyroid hormones and generating cellular energy.
Pregnant women in their second and third trimesters with low iron stores have significantly lower total thyroxine levels and higher thyroid-stimulating hormone levels compared to those with adequate iron stores.
Among pregnant women with borderline iodine deficiency during the second and third trimesters, 40% have low iron stores and 16% have total thyroxine levels below 100 nmol/L.
In pregnant women, levels of iron-related markers in the blood are statistically linked to the levels of thyroid-stimulating hormone and total thyroxine.
Iron deficiency produces the same symptoms as an underactive thyroid, such as fatigue and impaired thinking, because iron is necessary for transporting thyroid hormones and generating cellular energy.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.