Iron deficiency-related abortion and miscarriage burden among women of advanced maternal age: Insights from the Global Burden of Disease Study 2021.

Advanced maternal age (AMA) is associated with reduced fertility and higher risks of adverse pregnancy outcomes. Iron deficiency, a leading cause of anemia, has been associated with pregnancy loss. However, the iron deficiency-related burden among AMA women remains poorly quantified. This study aimed to quantify the global burden and geographical inequalities of abortion and miscarriage related to iron deficiency among AMA women. We utilized data from the Global Burden of Disease Study 2021. Trends from 1990 to 2021 in the age-standardized disability-adjusted life years rate and age-standardized mortality rate were quantified globally, across 5 Socio-demographic Index (SDI) regions and countries. Age-stratified analyses were performed. The association between SDI and age-standardized disability-adjusted life years rate/age-standardized mortality rate was evaluated using Spearman correlation analysis. Sensitivity analyses were also conducted. Globally, the iron deficiency-related burden of abortion and miscarriage in AMA women declined markedly, yet pronounced disparities persisted. The high-middle SDI region exhibited the most substantial decrease in disease burden, while the low SDI region continued to have the highest burden and showed slower improvement. A distinct pattern was observed in the low SDI region, where the peak burden shifted to the 45 to 49 age group, unlike all other SDI regions. A significant inverse correlation was observed between SDI and burden metrics, with a steeper inverse association at lower SDI levels and attenuation at higher SDI levels. The burden of iron deficiency-related miscarriage and abortion in AMA women decreased globally from 1990 to 2021, yet inequalities persist, especially in low SDI areas. The inverse correlation between SDI and disease burden suggests that regions with lower socioeconomic development may carry a disproportionately higher burden. These observations should be interpreted as population-level associations rather than causal relationships.