Early Pregnancy Metal Levels in Maternal Blood and Pregnancy Outcome

Abstract This study examines the association between early pregnancy maternal blood levels of Lead (Pb), arsenic (As), cadmium (Cd), and selenium (Se) and adverse pregnancy outcomes, while also addressing the differences between low-risk and high-risk groups based on having a history of preterm birth (PTB). This prospective cohort study recruited multigravida women at 11–13 gestational weeks, categorized into low-risk and high-risk groups. Participants completed a questionnaire, and heavy metal levels were measured in blood samples. Pregnancy outcomes were recorded following delivery. Multivariable analyses were conducted to evaluate the independent associations between heavy metal levels and pregnancy outcomes, while adjusting for variables associated with the metals levels based on the univariable analyses. Among 404 participants, the mean (± SD) levels were Pb: 3.12 ± 1.82 µg/L, As: 0.41 ± 0.4 µg/L, Cd: 0.26 ± 0.34 µg/L, and Se: 119.84 ± 21.05 µg/L. Significant differences in Pb, Se, Cd and As levels were observed between the low-risk and high-risk groups, with higher levels in the low-risk group. However, no significant associations were found between heavy metal levels and PTB, low birth weight (LBW), gestational age at delivery, birth weight, and head circumference in either univariable comparison or multivariable models, which adjusted for maternal age, BMI, employment, smoking, fertility treatments, and education. While significant differences in heavy metal levels were found between low-risk and high-risk groups, early pregnancy heavy metal levels showed no association with adverse pregnancy outcomes. These findings highlight the need for further research to understand the potential impact of these metals on pregnancy, considering population-specific factors and exposure timing.