In a collaborative research effort led by Caitlin Howe, PhD and Margaret Karagas, PhD of Dartmouth College, researchers observed an inverse association between the metalloid antimony and birth weight for gestational age, suggesting that this understudied metalloid may harm fetal growth. Their study, titled “Prenatal metal(loid) mixtures and birth weight for gestational age: a pooled analysis of three cohorts participating in the ECHO Program” is published in Environment International.
The study included approximately 1,000 mother-newborn pairs in three geographically and demographically diverse ECHO cohorts:
- The Maternal And Developmental Risks from Environmental and Social Stressors (MADRES) study, a predominantly lower-income Hispanic cohort in Los Angeles, California
- The New Hampshire Birth Cohort Study (NHBCS), a primarily non-Hispanic white cohort in northern New England
- The Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) study, a Hispanic cohort in northern Puerto Rico.
The team pooled data from these three cohorts, measured multiple metals in the mothers’ urine samples collected during pregnancy and evaluated the associations with birth weight for gestational age using a multipollutant analysis approach. In addition to the findings for antimony, the team reported that the effects of other metals (cobalt, mercury, nickel, tin) on birth weight for gestational age differed by cohort and/or infant sex. The mixture of metals together did not impact birth weight for gestational age. Cadmium and molybdenum individually were not associated with differences in birth weight for gestational age.
“Previous research on this topic has mainly focused on one metal at a time, but individuals are often exposed to multiple metals simultaneously, which may interact in complex ways to impact health,” said Howe.
This research highlights the need to identify major sources of antimony, which may differ depending on the population, such that interventions can be developed to reduce exposure to this toxic metalloid. In the future, the research team would also like to expand their analysis to additional ECHO cohorts and participants, investigate other biomarkers of metal and metalloid exposures, and identify windows in pregnancy when the developing fetus may be most susceptible to these exposures.