Fluoride Metabolism in Pregnant Women: A Narrative Review of the Literature

Abstract

Epidemiological studies use biomarkers of fluoride exposure in pregnant women as surrogate measures of fetal fluoride exposure; however, there is little understanding of how pregnancy affects fluoride metabolism and its biomarkers. This narrative review summarizes the changes of pregnancy that have the potential to impact fluoride’s absorption, distribution and excretion, and highlights the limited body of evidence on the topic. The physiologic systems that experience pregnancy-associated changes relevant to fluoride’s metabolism are the cardiovascular, renal, metabolic and gastrointestinal, as well bone and calcium metabolism and the body’s acid-base balance. The available evidence indicates that fluoride is found in the maternal plasma and urine, placenta, amniotic fluid and fetus. Although plasma and urinary fluoride vary across gestation, there is insufficient quality evidence to determine the direction or extent of such variation. Furthermore, there is no doubt that fluoride from maternal blood crosses the placenta and is absorbed and excreted by the fetus; however, the biological mechanisms behind this placental passage are unknown. Research on maternal and prenatal biomarkers of fluoride exposure would benefit from studies on how pregnancy-associated changes affect the metabolism of fluoride across gestation, the mechanisms for the intestinal absorption of fluoride in pregnant women, and the placental passage of fluoride.

"Cultura anfibia": etnoarqueología en una comunidad pesquera del Caribe Colombiano

“…Incluyen con estos nombres chistes de doble sentido con connotación sexual. El nombrar los sitios indica una apropiación del territorio marino que se construye por las prácticas cotidianas y que funciona como cohesionadora social, además comprende un conocimiento espacial y ecológico (Figura 3) (ACHESON, 1981;ALVAREZ, 2021;ANDREIS, 2007;CAMARCO;CAMACHO, 2019;MÁRQUEZ, 2021;CASTIBLANCO;VALLEJO, 2020;FORMAN, 1967;SÁNCHEZ et al, 2019;SILVA, 2021). En el Cuadro 1 se presentan las etapas de la obtención y procesamiento de los peces de la investigación etnográfica y, en la Figura 4 se detalla la ubicación de las etapas de pesca y recolección de moluscos de la observación etnográfica.…”

Impact of Fluoride Exposure on Rat Placenta: Foetal/Placental Morphometric Alterations and Decreased Placental Vascular Density

“…Likewise, alterations in oxidative stress markers [ 8 , 9 ] and decreased fertility in rats [ 10 , 11 ] have been reported; however, information on placental alterations caused by fluoride exposure is very limited. However, there is available evidence indicating that fluoride in the mother’s blood crosses the placenta and is absorbed and excreted by the foetus [ 12 ]. The placenta is the temporary organ that fulfils the functions of hormone secretion, metabolic transfer, gas exchange and foetal protection and, therefore, is one of the organs most exposed to contaminant damage [ 13 ].…”