Iodine Nutrition as a Potential Determinant of Maternal Depression During Pregnancy and the Postpartum Period: A...

Although iodine deficiency is well established as a contributor to thyroid dysfunction, its relationship with perinatal depressive symptoms remains unclear This scoping review synthesizes evidence on maternal iodine status and supplementation in relation to depressive symptoms during pregnancy and the postpartum period. Following the PRISMA-ScR guidelines, 5 databases (PubMed/MEDLINE, Embase, Scopus, Web of Science, Cochrane Library) were searched for studies published from 2000 to 2025. Eligible studies included populations of healthy pregnant or postpartum women reporting iodine status (urinary iodine concentration, dietary intake, or supplementation) and mental health outcomes, including depression, anxiety, or emotional distress. Two authors independently screened studies, extracted data, and assessed quality using the Joanna Briggs Institute tools. Eight studies were included: 4 examined iodine status and 4 assessed iodine supplementations. Low maternal iodine intake was consistently associated with higher postpartum depressive symptoms and anhedonia, even without overt thyroid dysfunction. Supplementation or fortification was evaluated across diverse populations using iodized salt, iodine-containing supplements, or iodized oil. While supplementation addressed iodine deficiency, its impact on maternal mood was inconsistent, with some studies showing no effect and others suggesting potential increases in emotional distress under specific conditions. Both inadequate and excessive iodine intake may affect maternal mood during pregnancy and the postpartum period, emphasizing the importance of maintaining optimal iodine nutrition. Although iodine is crucial for supporting maternal and fetal thyroid function, the effectiveness of iodine supplementation/fortification in preventing perinatal depressive symptoms remains unclear. Well-designed, longitudinal studies are needed to determine the optimal iodine intake for promoting maternal mental health.