The Claim
In pregnant women during the second and third trimesters, negative body iron stores are associated with a 7.8-fold higher relative risk of total thyroxine (TT4) levels below 100 nmol/L and a strong tendency for elevated thyroid-stimulating hormone (TSH) levels above 4.0 mU/L.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
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.
See the scientific wording
In pregnant women during the second and third trimesters, negative body iron stores are associated with a 7.8-fold higher relative risk of total thyroxine (TT4) levels below 100 nmol/L and a strong tendency for elevated thyroid-stimulating hormone (TSH) levels above 4.0 mU/L, suggesting that iron deficiency co-occurs with impaired thyroid hormone status in pregnancy.
When the body lacks iron, the thyroid gland cannot make enough thyroid hormone because iron is needed for the enzyme that builds it. With less thyroid hormone in the blood, the brain signals the thyroid to work harder, causing a rise in the hormone that tells the thyroid to produce more.
What the research says
1 studyStudy: Iron deficiency predicts poor maternal thyroid status during pregnancy.
Pregnant women with low iron levels were much more likely to have low thyroid hormone and high TSH levels, meaning their thyroid wasn't working as well. This shows that iron and thyroid health are linked during pregnancy.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.