Maternal-child exposure to metals during pregnancy in Rio de Janeiro city, Brazil: The Rio Birth Cohort Study of Environmental Exposure and Childhood Development (PIPA project)

Background: Environmental metal exposure during pregnancy can affect intrauterine growth and disrupt child development. Metal exposure in urban areas can occur through the air, water and food routes. The city of Rio de Janeiro is the second more populous of Brazil and the sixth most populous in the American continent and is characterized by a significant social-economic inequality and a large range of urban organization problems. Objectives: To evaluate environmental heavy metal (arsenic, cadmium, lead and mercury) exposure in mother-newborns pairs in an urban area in Rio de Janeiro, Brazil. Methods: All pregnant women, over 16 years of age, who came to the University Maternity School for newborn delivery orientation, between October and November 2017, were invited to participate in the project. Socioeconomic, cultural, leisure, and living conditions data of from the parents were collected via questionnaire; whole maternal blood and umbilical cord blood samples were also collected. Results: Of the 209 eligible pregnant women 142 (68%) accepted the invitation to participate in the study. A total of 131 (92.3%) mothers delivered live born children, and maternal blood and umbilical cord blood were collected from 117 mother-newborn pairs. Metal concentrations above the detection limit were detected in all maternal and cord blood samples. Strong correlations of arsenic, cadmium, lead and mercury concentrations between maternal and umbilical cord blood were observed. Median lead and arsenic concentrations in maternal and umbilical cord blood were higher than values reported in other studies conducted in Brazil and worldwide. Lead concentrations in 25% of the umbilical cord blood samples were near of 5 mu g/dL (P75 = 4.92 mu g/dL). Conclusion: The results reported herein indicate the need for the establishment of health surveillance programs in Brazil, in order to investigate and monitor the health effects of environmental heavy metal exposure in children since the gestation period.