Association of arsenic exposure and clinical hematological changes during pregnancy: Findings from a prospective Wuhan birth cohort study

Background: Animal studies have reported arsenic-induced disturbed erythropoiesis parameters. However, the effects of exposure to arsenic on hematological parameters among pregnant women are unclear.Objectives: We aimed to evaluate trimester-specific associations between arsenic metabolites and erythropoietic parameters measured repeatedly during pregnancy.Methods: A total of 1945 pregnant women from a birth cohort study were included. We detected arsenic species in urine sampled at each trimester and extracted erythropoietic parameters in different trimesters from the medical records. We used linear regressions with generalized estimating equations (GEEs) to examine the relationship between arsenic metabolites concentrations at different trimesters and erythropoietic parameters. We utilized GEEs to calculate the odds ratio (OR) for anemia during pregnancy.Results: Adjusted trimester-specific analysis showed that higher monomethylated arsenic (MMA) and %MMA were related to remarkably reduced hemoglobin (Hb) and mean corpuscular hemoglobin (MCH). Additionally, elevated urinary MMA concentration and %MMA in the early trimester were associated with an increased risk of microcytic anemias in the late trimester.Conclusions: Our study demonstrated a significant inverse relationship between gestational arsenic exposure and Hb and MCH. Notably, higher MMA and lower methylation capacity to metabolize inorganic arsenic (iAs) in early pregnancy might increase the likelihood of microcytic anemia among pregnant women in late pregnancy.