Iron Supplementation in Pregnancy and Risk of Gestational Diabetes: A Narrative Review

• Published in: Nutrients 2022-11, Vol.14 (22), p.4791
• Main Author: Petry, Clive J
• Format: Article
• Language: English
• Subjects: Anemia; Anemia - drug therapy; Blood; Clinical trials; Cohort analysis; Complications; diabetes; Diabetes in pregnancy; Diabetes mellitus; Diabetes, Gestational - etiology; Dietary supplements; Dietary Supplements - adverse effects; Female; Food and nutrition; Gestational diabetes; Health aspects; Health risks; Hemoglobin; Heterogeneity; Humans; Insulin; Insulin resistance; Insulin secretion; Iron; Iron - adverse effects; Iron in the body; Iron Overload - complications; Meta-analysis; micronutrients; Oxidation resistance; Oxidative stress; Pregnancy; Pregnancy complications; Pregnant women; Review; Risk analysis; Risk factors
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu14224791

Pregnant women frequently supplement their diets with iron to treat any cryptic anemia, on the assumption that if anemia is not present, there will be no negative consequences. However, in women who are already iron-replete, it has been suggested that this can lead to iron overload and an increased risk of certain pregnancy complications. One such complication is gestational diabetes. Fourteen clinical trials, case-control or cohort studies (found using Pubmed/Scopus/Web of Science) have investigated links between iron supplementation in pregnancy and risk of gestational diabetes, several of them finding significant associations with increased risk. Potential mechanisms include increased oxidative stress leading to insulin resistance and inadequate compensatory insulin secretion. Current evidence suggests that dietary supplementation with iron in pregnancy may increase a pregnant woman's chance of developing gestational diabetes, although available evidence is somewhat contradictory, and the magnitude of any increased risk appears relatively small. Meta-analyses have suggested the presence of significant heterogeneity in results between studies, urging a degree of caution in interpreting these results. It is currently suggested that advice to pregnant women about whether to supplement their diets with iron or not should consider both their current iron status and their other established risk factors for gestational diabetes.