Cord Blood Mercury Levels Research Articles

Assessment of lead and mercury levels in maternal blood, fetal cord blood and placenta in pregnancy with intrauterine growth restriction

Introduction: Many studies reported that prenatal exposure to lead and mercury are correlated with reduced birth weight and size, and these metals can cause adverse effects on neurodevelopment. In this study, it was aimed to investigate and compare the lead and mercury levels in maternal blood, cord blood, and placenta in pregnant women with IUGR fetuses diagnosed using abnormal Doppler findings and pregnant women with healthy fetuses.
 Material: This study included 75 patients, comprising 41 in IUGR group and 34 in control group. Maternal venous blood, fetal cord blood and placental samples were taken during delivery period.
 Results: Mercury levels in maternal blood and fetal cord blood, and lead levels in the placenta were found to be significantly higher in the IUGR group than in healthy subjects. Correlation analysis revealed that measurement values of body weight, body height, and head circumference of fetus might be lower when mercury level was measured higher in maternal blood and fetal cord blood. Furthermore, fetal body weight and fetal body height also would be lower when lead level measured in placenta was higher. Logistic Regression analysis results revealed that mercury levels measured in fetal cord blood could be used as the best marker in predicting low fetal weight, low fetal body height, and low fetal head circumference.
 Conclusion: In conclusion, it was thought with this study results that in order to identify the etiology and to give therapeutic prenatal care of the IUGR in a fetus diagnosed as idiopathic IUGR it would be appropriate to measure the level of lead and especially mercury in the fetal cord blood during the prenatal follow-up period.

Pre and postnatal exposure to mercury and respiratory health in preschool children from the Spanish INMA Birth Cohort Study

Effects of mercury on maturing immune system have been reported, however the association with respiratory and allergy problems during infancy remains unclear. The aim of this study is to evaluate the association between pre and postnatal mercury exposure and respiratory and allergy problems among preschool children and to examine the role of potential modifying factors. Study subjects were children participant in Spanish Childhood and Environment Project (INMA, 2003–2008). We measured total mercury levels in cord blood (n = 1868) and hair at 4 years of age (n = 1347). Respiratory outcomes (wheezing, severe wheezing, chestiness, persistent cough, eczema and otitis) were obtained by questionnaires administered to parents. Associations were investigated by logistic regression adjusted for socio-demographic and lifestyle-related variables in each cohort and subsequent meta-analysis. We tested effect modification by factors related to individual susceptibility, diet and co-exposure with other pollutants. The geometric mean of cord blood and hair total mercury was 8.20 μg/L and 0.97 μg/g, respectively. No statistically significant association between pre or postnatal mercury exposure and respiratory and allergy outcomes was found. Notwithstanding, lower maternal intake of fruits and vegetables increased the risk of some respiratory outcomes due to the prenatal exposure to mercury (pint < 0.05). Moreover, an inverse association between prenatal mercury exposure and some respiratory outcomes was observed among children with higher maternal exposure to organocholorine compounds or smoking (pint < 0.05). Also, sex and postnatal smoking exposure modulated mercury postnatal effects on persistent cough (pint < 0.05). In conclusion, no association between pre and postnatal mercury exposure and respiratory and allergy problems among the whole population at study was found. However, diet and other toxicants could modulate this relation, especially during prenatal period. More research on this topic is warranted due to the limited evidence.

Adverse effects of prenatal mercury exposure on neurodevelopment during the first 3 years of life modified by early growth velocity and prenatal maternal folate level

Background and aimsPrevious studies have suggested that mercury exposure and folate levels during pregnancy may influence early childhood neurodevelopment. Rapid catch-up growth in children is associated with an increased risk of pathological nervous system development. We evaluated whether the association between prenatal folate and mercury-related neuropsychological dysfunction was modified by growth velocity during childhood. MethodsThe Mothers and Children's Environmental Health (MOCEH) birth cohort study began in 2006 and by 2010, 1751 women had been enrolled before the second trimester of their pregnancy along with their partners. Participants visited the research center at birth and 6, 12, 24, and 36 months. We measured mercury levels in maternal and cord blood and folate in maternal serum. Questionnaires to evaluate the environment and health of their child were administered and anthropometric factors including body weight and height were measured. Certified investigators used the Bayley test to measure neurobehavioral outcomes. We calculated postnatal growth change as the change in infant weight for-age z-score between birth and 3 years. Multiple linear regression and mixed models were used to examine the association between mercury exposure and children's neurodevelopment as well as the modifying effects of folate and growth velocity. ResultsA total of 30.6% of children experienced rapid growth during the first 3 years of life. Median values of mercury in the low folate group were significantly higher in rapid growers (3.41 μg/L in maternal blood and 5.63 μg/L in cord blood) than in average/slow growers (3.05 μg/L in maternal blood and 5.19 μg/L in cord blood). Rapid growers were also significantly associated with decreased psychomotor development scores during the first 3 years of life and with having mothers who had low prenatal folate levels, even after adjusting for potential confounders. ConclusionPrenatal mercury exposure adversely affects infant neurodevelopment and is associated with rapid growth during the first 3 years of life. This effect was limited to children whose mothers had low prenatal folate levels, suggesting a protective effect of folate against developmental neurotoxicity due to mercury exposure and rapid catch-up growth.

A Global Look at Mercury Exposures: Supporting the Goals of the Minamata Convention.

A Global Look at Mercury Exposures: Supporting the Goals of the Minamata Convention.

Effect of Fish Frequency Consumption on Serum Mercury Levels in Pregnant Mothers and their Newborns

Mercury is a ubiquitous cumulative element which is existed and contaminated in many forms; the most common route is fish intake. The purpose of this work was to study the link between the rate of fishy food consumption and serum mercury level in both pregnant mothers and cord blood of their newborns. This study consisted of 70 pregnant women and their neonates. The study samples were collected from the maternal blood and cord blood of their newborns at the delivery time. The mean of gestational age for their neonates is (36.9 ± 2.1) weeks. Detailed food frequency questionnaire was taken to evaluate the frequency of fish consumption per week, and approximate frequency per month. Measurement of serum mercury level was done using inductive coupled plasma mass spectrometry. This study finds highly significant increase (P ˂0.01) in serum mercury level either in maternal blood or in their newborns’ cord blood in a manner dependent on the frequency of fish consumption. High significant positive correlation (P ˂0.01) has been recorded between maternal mercury level and cord blood mercury level of their newborns. Also, the frequency of fish consumption is high significantly correlated with mercury level in each of maternal blood and cord blood of their newborns (P ˂0.01). Hence, the study concludes that mercury tends to accumulate in fish food chains reaching the human beings. Frequency of fish consumption per month affects the level of mercury in mothers and their neonates.

Relation of prenatal low-level mercury exposure with early child neurobehavioral development and exploration of the effects of sex and DHA on it

BackgroundThe extent to which low-level, in utero mercury exposure affects child neurobehavioral development during early childhood has been inconclusive. In addition, the effects of sex and docosahexaenoic acid (DHA) on these relationships remain unclear and controversial. ObjectivesThis study aimed to explore the associations between prenatal low-level mercury exposure and child neurobehavioral development during the neonatal and toddler periods and to examine the potential confounding or interactive effects of sex and DHA status on these relationships. MethodsThis longitudinal study included 286 mother-child pairs in Shanghai, China, whose cord blood samples were analyzed for total mercury, DHA, other nutrients and coexposure contaminants possibly due to maternal consumption of seafood. Children's neurobehavioral development was assessed with the Neonatal Behavioral Neurological Assessment (NBNA) three days after birth and the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) at 18 months of age. ResultsCord blood mercury concentration, with geometric mean of 2.00 μg/l, was related to poorer NBNA performance but unrelated to BSID-III scores with adjustment for DHA and other covariates. Cord serum DHA was positively associated with motor development assessed by the BSID-III. The interaction was found between mercury and DHA on the NBNA score, and the inverse relation of cord blood mercury with NBNA was significant only among the children with lower DHA levels (<45.54 μg/ml). Additional adjustment for DHA didn't change the associations between cord blood mercury and neurodevelopmental outcomes substantially. The mercury by sex interaction for language of BSID-III was borderline significant. ConclusionsOur research provides initial evidence for the negative effects of prenatal low-level mercury exposure on neonates' neurobehavioral development. Prenatal DHA status may modify the relationship between cord blood mercury level and neonatal neurobehavioral development, but the confounding effects of DHA were not observed. Further studies are warranted before the causality of the observed associations can be determined.

Human Exposure to Mercury during the Last Half-Century: Worldwide Trends in Human Blood and Breast Milk Levels and Their Implications on Health

Mercury is a pollutant of global concern. It has been found in various biological media including human blood and breast milk, globally. This study assesses global and regional trends of mercury levels in human blood and breast milk in the last half-century. This study also provides an overview of epidemiological literature showing evidence of associations between mercury exposure and various human health conditions.We searched electronic databases to identify articles published prior to June 14, 2017. Our search finalized a pool of 562 studies reporting total mercury levels in whole blood, cord blood, or breast milk and associations with human health conditions. Temporal trends of mercury levels in target media were estimated using a linear fit of the log-transformed data. Choropleth maps were created to provide an overview of worldwide mercury levels in human blood and breast milk. Furthermore, a summary of significant and relevant associations between mercury exposure and human health conditions in children and adults was prepared.We found significant declines in mercury levels in whole blood, cord blood, and breast milk between 1966&amp;#8211;2015. A regional overview of mercury exposure suggests highest levels in South America, followed by Africa and Asia. Populations from North America and Europe were found with the lowest mercury exposure levels. We observed conclusive consistent associations of mercury exposure with only selected health conditions, especially neurodevelopment and neurotoxicity in children and adults. For several other health conditions, reported findings do not support conclusive associations.Our study establishes a baseline for the evaluation of mercury levels and health risks that will be measured under the Minamata Convention in the future and highlights the demand for well-designed epidemiological investigations to fully understand the health implications of mercury exposure.

Mercury Materno-fetal Burden and Its Nutritional Impact.

BACKGROUND:Mercury exists worldwide in food, water and air throwing its health hazards on all body systems.AIM:To show the influence of the presence of mercury in pregnant mothers’ blood on its level in the umbilical cord blood; and to display the relationship between the different foodstuff on the mercury levels in pregnant mothers’ and umbilical cord blood.PATIENTS AND METHODS:This cross-sectional study was conducted on randomly chosen 113 pregnant mothers at the time of labour and on their newborns. Full history, sociodemographic data and food frequency questionnaire for dietary assessment were recorded. The Maternal and neonatal anthropometric measurements together with the Apgar scoring were also measured. Serum mercury levels in both mothers’ and umbilical cord blood were measured using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS).RESULTS:A high percentage of mothers (82.3%) were exposed to passive smoking. There was a statistically significant positive correlation between the maternal and fetal umbilical cord blood mercury levels (p = 0.002). There was an insignificant negative correlation between the maternal blood and fetal umbilical cord blood mercury levels on one side and each of the different foodstuff on the other side (fish, vegetables, fruits and proteins, for example, meat and legumes). An insignificant positive correlation was found between dairy products and of the maternal blood and umbilical cord blood mercury levels.CONCLUSION:The fetal umbilical cord blood mercury levels correlate positively with the maternal blood mercury. The different foodstuff can influence the maternal and umbilical cord blood mercury levels whether by increase or decrease. Strict measures should be taken to decrease environmental mercury contamination with attention to pregnant mothers.

Prenatal mercury exposure and birth weight

Adverse effects of prenatal mercury exposure on pregnancy outcomes remain a public health concern. We assessed the relationship between prenatal mercury exposure and newborn anthropometric characteristics in 334 mother-child pairs from the early stages of pregnancy to delivery in Tokyo, Japan, between December 2010 and October 2012. We found a negative correlation between blood mercury levels during the first and second trimesters of gestation and birth weight (r = −0.134 and −0.119, respectively; p < 0.05). Multiple linear regression analysis confirmed the relationship between first-trimester maternal blood mercury levels and birth weight when adjusted for independent variables (β = −0.170, t = −2.762; p = 0.006). Mean mercury levels in umbilical cord blood were twice as high as maternal blood levels (10.15 ± 7.74 and 4.97 ± 3.25 μg/L, respectively; r = 0.974, p < 0.001). Our findings suggest that pregnant women and women of reproductive age should avoid mercury exposure, even at low levels, because of its potentially adverse effects on fetal development.

Stability of cognitive development during the first five years of life in relation to heavy metal concentrations in umbilical cord blood: Mothers' and Children's Environmental Health (MOCEH) birth cohort study

The objective of this study was to investigate stability of cognitive development during the first five years of life in relation to heavy metal concentrations in umbilical cord blood in Korean children. This research is part of the Mothers' and Children's Environmental Health (MOCEH) study, a multi-center prospective birth cohort study of pregnant women in Korea who were recruited from 2006 to 2010. We analyzed the complete follow-up data of children who were 5years-old in 2016. We measured lead, mercury, and cadmium levels in the umbilical cord blood of 251 children, and analyzed them, for whom neurodevelopmental data were available. We determined stability of cognitive development scores using three methods. First, we used partial correlation analyses to examine the stability of cognitive development at each measurement time. Second, we used Cramer's V to investigate the magnitude and direction of changes in cognitive development scores at each follow-up period among three groups (high, medium, and low scores). The results showed that cognitive development scores measured at the closest times had the strongest correlations, and the stability of cognitive development scores increased with age, from 6 to 60months. Groups at the extreme ends of cognitive development (high or low scores) had more stable scores, and this tendency was also stronger in infants >24months-old. The stability of cognitive development was unrelated to the umbilical cord level of heavy metals, based on analysis with Fisher's transformation. In conclusion, the present study showed that the cognitive development scores in a cohort of infants (6 to 60months-old) were stable.

Association of food consumption during pregnancy with mercury and lead levels in cord blood

In utero exposure to mercury and lead has been linked to various adverse health effects related to growth and development. However, there was no evidence on the relationship between food consumption during pregnancy and mercury or lead level in cord blood. Therefore we measured mercury and lead levels in bloods, urines, and cord bloods obtained from 302 pregnant women and estimated relationships between food consumption during pregnancy and mercury or lead level in cord blood to identify perinatal mercury and lead exposures originated from foods during pregnancy. Relationship between food consumption and mercury or lead level was estimated using a generalized linear model after adjustment for body mass index (BMI), delivery experience, income, recruitment year, and other dietary factors for mercury and age, BMI, cesarean section, delivery experience, recruitment year, and other dietary factors for lead. Fish consumption was positively associated with mercury level in cord blood (p=0.0135), while cereal and vegetable consumptions were positively associated with lead level in cord blood (p=0.0517 for cereal and p=0.0504 for vegetable). Furthermore, tea consumption restrained increase of lead level in cord blood (p=0.0014). Our findings support that mercury or lead exposure in Korean pregnant women may come from frequent fish and cereal or vegetable consumption while tea consumption may decrease lead exposure in pregnant women. Therefore, careful intervention through food consumption should be considered.

Impact of fetal and childhood mercury exposure on immune status in children

BackgroundMercury exposure have been shown to affect immune status in animals as reflected by cytokine expression. It is unclear whether low levels of exposure during fetal and/or childhood periods could impact on immune status in humans. ObjectivesTo test the hypothesis that fetal and childhood mercury exposure is associated with childhood cytokine profiles and to investigate whether childhood selenium levels interact with any of the associations found. MethodsChildren were recruited from a previously established birth cohort between the ages of 6–9 years for assessment and measurement of blood mercury, selenium and cytokine profile (interleukin (IL)-4, IL-6, IL-8, IL-10, IL-13 and TNF-alpha). Multivariable linear regression models were used to assess the adjusted association of cord blood mercury concentration and current mercury concentrations with levels of the cytokine levels. We tested whether the association with current mercury level varied by current selenium level and cord blood mercury level. ResultsIL-10 was negatively associated with current blood mercury concentration. The effect was greatest in cases with low cord blood mercury and low current selenium concentrations. None of the other cytokine levels were associated with either cord blood or current blood mercury concentrations, except that cord blood mercury was negatively associated with IL-6. ConclusionsChildhood mercury exposure was negatively associated with childhood IL-10 levels. It is postulated that while selenium is protective, low levels of fetal mercury exposure may increase the degree of this negative association during childhood. Further studies into the clinical significance of these findings are required.

Maternal risk factors associated with lead, mercury and cadmium levels in umbilical cord blood, breast milk and newborn hair

Objective: Lead (Pb), mercury (Hg) and cadmium (Cd) are environmental pollutants that are wide spread throughout the world. The present study aimed to investigate the level of exposure to Pb, Hg and Cd during the prenatal period, and the possible routes of maternal exposure to these toxic heavy metals.Participants: The study included 123 mothers and their newborns. Umbilical cord blood samples were collected immediately after delivery, and breast milk and newborn hair samples were collected between postpartum d 3 and 10.Results: Among the 121 cord blood samples that were analyzed, Pb was present in 120 (99.2%) and the mean level was 1.66 ± 1.60 µg dL−1 (range: <detection limit–12.50 µg dL−1), whereas Hg was noted in only 2 (1.7%) (15.74 and 33.20 µgL−1) and Cd was detected in 24 (19.8%) (range: < detection limit–6.71 µgL−1). The level of Pb in cord blood was ≥2 µg dL−1 in 29% of the samples. Pb, Hg and Cd were detectable in all the newborn hair samples.Discussion: Among the 107 breast milk samples analyzed, 89 (83.2%) had a detectable level of Pb and the mean level was 14.56 ± 12.13 µgL−1. Detection rate of Cd in breast milk was higher in women who resided near to city waste disposal site. Detection rate of Cd in cord blood was significantly higher in the women who consumed ≥2 servings of fish weekly. Maternal exposure to environmental tobacco smoke (ETS) resulted in elevated levels of Pb and Cd in newborn hair samples.Conclusion: Most of the study samples had detectable levels of Pb, Hg and Cd, indicating that there was long-term maternal exposure prior to and during pregnancy, and a considerable number of the cord and breast milk samples had levels that exceeded the present accepted safety level.

Umbilical cord blood and placental mercury, selenium and selenoprotein expression in relation to maternal fish consumption

Seafood is an important source of nutrients for fetal neurodevelopment. Most individuals are exposed to the toxic element mercury through seafood. Due to the neurotoxic effects of mercury, United States government agencies recommend no more than 340g (12oz) per week of seafood consumption during pregnancy. However, recent studies have shown that selenium, also abundant in seafood, can have protective effects against mercury toxicity. In this study, we analyzed mercury and selenium levels and selenoprotein mRNA, protein, and activity in placenta of a cohort of women in Hawaii in relation to maternal seafood consumption assessed with dietary surveys. Fish consumption resulted in differences in mercury levels in placenta and cord blood. When taken as a group, those who consumed no fish exhibited the lowest mercury levels in placenta and cord blood. However, there were numerous individuals who either had higher mercury with no fish consumption or lower mercury with high fish consumption, indicating a lack of correlation. Placental expression of selenoprotein mRNAs, proteins and enzyme activity was not statistically different in any region among the different dietary groups. While the absence of seafood consumption correlates with lower average placental and cord blood mercury levels, no strong correlations were seen between seafood consumption or its absence and the levels of either selenoproteins or selenoenzyme activity.

Increased mercury release from dental amalgam restorations after exposure to electromagnetic fields as a potential hazard for hypersensitive people and pregnant women.

Over the past decades, the use of common sources of electromagnetic fields such as Wi-Fi routers and mobile phones has been increased enormously all over the world. There is ongoing concern that exposure to electromagnetic fields can lead to adverse health effects. It has recently been shown that even low doses of mercury are capable of causing toxicity. Therefore, efforts are initiated to phase down or eliminate the use of mercury amalgam in dental restorations. Increased release of mercury from dental amalgam restorations after exposure to electromagnetic fields such as those generated by MRI and mobile phones has been reported by our team and other researchers. We have recently shown that some of the papers which reported no increased release of mercury after MRI, may have some methodological errors. Although it was previously believed that the amount of mercury released from dental amalgam cannot be hazardous, new findings indicate that mercury, even at low doses, may cause toxicity. Based on recent epidemiological findings, it can be claimed that the safety of mercury released from dental amalgam fillings is questionable. Therefore, as some individuals tend to be hypersensitive to the toxic effects of mercury, regulatory authorities should re-assess the safety of exposure to electromagnetic fields in individuals with amalgam restorations. On the other hand, we have reported that increased mercury release after exposure to electromagnetic fields may be risky for the pregnant women. It is worth mentioning that as a strong positive correlation between maternal and cord blood mercury levels has been found in some studies, our findings regarding the effect of exposure to electromagnetic fields on the release of mercury from dental amalgam fillings lead us to this conclusion that pregnant women with dental amalgam fillings should limit their exposure to electromagnetic fields to prevent toxic effects of mercury in their fetuses. Based on these findings, as infants and children are more vulnerable to mercury exposures, and as some individuals are routinely exposed to different sources of electromagnetic fields, we possibly need a paradigm shift in evaluating the health effects of amalgam fillings.

Elevated prenatal methylmercury exposure in Nigeria: Evidence from maternal and cord blood

Methylmercury is a neurodevelopmental toxicant that is globally distributed though little is known about prenatal exposures in sub-Saharan Africa. The objective of the current study was to measure total mercury levels in cord blood and maternal blood from 95 mother-newborn pairs recruited from hospitals in Nnewi, Nigeria. The secondary aims of the study were to explore if demographic and dietary factors were associated with blood mercury levels, and to explore if mercury levels were associated with any self-reported health outcome and childbirth outcome. Maternal blood mercury levels averaged 3.6μgL−1 and ranged from 1.1μgL−1 to 9.5μgL−1. Cord blood mercury averaged 5.1μgL−1 and ranged from 1.2μgL−1 to 10.6μgL−1. The mean ratio of mercury in paired cord blood to maternal blood was 1.5 and it ranged from 0.4 to 3.2. Mercury in maternal and cord blood were significantly correlated (r=0.471). More than one-third of mothers reported eating fish at least once per day, and a weak (p=0.08) fish consumption-related increase in blood mercury was found. Cord blood mercury was positively and significantly associated with birth weight and length, and head and chest circumference. Mercury levels in 36% of the participants exceeded the biomonitoring guideline associated with the United States Environmental Protection Agency (U.S. EPA) reference dose for mercury. The study shows that pregnant women and their newborns are exposed to methylmercury and that their exposures are higher compared to general populations sampled from other regions of the world.

Exposure to mercury among Spanish preschool children: Trend from birth to age four

The purpose of this study is to describe the total hair mercury concentrations and their determinants in preschool Spanish children, as well as to explore the trend in mercury exposure from birth to the age four. This evolution has been scarcely studied in other birth cohort studies.The study population was 580 four year old children participating in the INMA (i.e. Childhood and Environment) birth cohort study in Valencia (2008–2009). Total mercury concentration at age four was measured in hair samples by atomic absorption spectrometry. Fish consumption and other covariates were obtained by questionnaire. Multivariate linear regression models were conducted in order to explore the association between mercury exposure and fish consumption, socio-demographic characteristics and prenatal exposure to mercury.The geometric mean was 1.10µg/g (95%CI: 1.02, 1.19). Nineteen percent of children had mercury concentrations above the equivalent to the Provisional Tolerable Weekly Intake proposed by WHO. Mercury concentration was associated with increasing maternal age, fish consumption and cord blood mercury levels, as well as decreasing parity. Children whose mothers worked had higher mercury levels than those with non working mothers. Swordfish, lean fish and canned fish were the fish categories most associated with hair mercury concentrations. We observed a decreasing trend in mercury concentrations between birth and age four. In conclusion, the children participating in this study had high hair mercury concentrations compared to reported studies on children from other European countries and similar to other countries with high fish consumption. The INMA study design allows the evaluation of the exposure to mercury longitudinally and enables this information to be used for biomonitoring purposes and dietary recommendations.

Effect of Low-Level Prenatal Mercury Exposure on Neonate Neurobehavioral Development in China

BackgroundThis study aimed to assess the effects of low-level prenatal mercury exposure on neonate neurobehavioral development in China. MethodsIn total, 418 mother-neonate pairs were included in the study. Maternal urine, hair, and blood samples and cord blood samples were used to document prenatal exposure to mercury. The Neonatal Behavioral Neurological Assessment was used to estimate neurobehavioral development in the neonates at 3 days of age. ResultsTotal mercury level was significantly higher in cord blood than that in maternal blood. A strong correlation was found between total mercury levels in maternal blood and those in cord blood (r = 0.7431; P < 0.0001). Trend analysis revealed that mothers who consumed more fish had higher blood and cord blood mercury levels (all P < 0.0001). Significant differences were also found between male and female cord blood mercury levels among groups with different fish consumption frequencies (all P < 0.0001). Cord blood mercury level was significantly associated with total Neonatal Behavioral Neurological Assessment scores (β = 0.03; standard error = 0.01; P = 0.0409), passive muscle tone (odds ratio = 1.07; 95% confidence interval = 1.12-1.13; P = 0.0071), and active muscle tone (odds ratio = 1.06; 95% confidence interval = 1.01-1.11; P = 0.0170) scores after adjustment, respectively. ConclusionsNeonatal neurodevelopment was associated with prenatal exposure to mercury. Women with high mercury levels should avoid intake seafood excessively during pregnancy. Long-term effects of exposure to mercury on childhood development need to be further explored.

Differences in prenatal exposure to mercury in South African communities residing along the Indian Ocean

Mercury is a persistent environmental pollutant that has the potential to adversely affect human health, particularly, foetal neurodevelopment. The purpose of the study was to investigate prenatal mercury (Hg) exposure in the population in three sites along the South Africa coast. Study subjects included women (n=350) who were admitted for delivery at the local hospitals. Maternal and cord blood samples were collected to measure total mercury and each participant was required to answer a questionnaire. The 90th percentile of mercury levels in maternal and cord blood of the total population was 1.15μg/l and 1.67μg/l, respectively. Site 1 (Manguzi) participants had the highest maternal geometric mean (GM) values of 0.93μg/l, which was significantly different from Site 2 (Port Shepstone) (0.49μg/l) and Site 3 (Empangeni) (0.56μg/l) (ANOVA test, p<0.001). Umbilical cord blood GM Hg level for Site 1 (1.45μg/l) was more than double the GM Hg level in Site 2 (0.70μg/l) and Site 3 (0.73μg/l). Univariate analysis indicated that the following maternal characteristics were positive predictors for elevated umbilical cord Hg levels: maternal blood Hg levels, living with a partner, residing in Site 1, living in informal housing, using wood and gas for cooking, borehole water as a drinking source, and a member of the household being involved in fishing. Maternal dietary predictors of elevated Hg levels in umbilical cord blood included consuming fresh fish, tinned fish, fruit or dairy products, daily. This study provides baseline data and reveals that 2% of the study population were above the EPA's reference value (5.8μg/l) suggesting low level exposure to mercury in pregnant women and the developing foetus in South Africa. Further research is required to explore the sources of elevated Hg levels in Site 1.

In utero exposure to environmental lead and manganese and neurodevelopment at 2 years of age

Background and objectiveManganese, lead, arsenic and mercury are common neurotoxic metals in the environment. Nonetheless, the relationship between prenatal exposure to low doses of neurotoxic metals and neurodevelopment in children is not clear. The objective of this study was to explore the relationship between in utero exposure to environmental neurotoxic metals and neurodevelopment at 2 years of age. MethodsThe population of this study came from the Taiwan Birth Panel Study. We included 230 pairs of non-smoking mothers without any occupational exposure and their singleton full-term children. The information about exposure during pregnancy was obtained using a structured questionnaire, and the manganese, lead, arsenic and mercury levels in umbilical cord blood samples were analyzed using inductively coupled plasma mass spectrometry. We used the Comprehensive Developmental Inventory for Infants and Toddlers (CDIIT) to evaluate the developmental status of each child at 2 years of age, and we examined the association of in utero exposure to environmental metals and neurodevelopment using linear regression models. ResultsThe median concentrations of manganese, lead, arsenic and mercury in the cord blood samples in this study were 47.90µg/L (range, 17.88–106.85µg/L), 11.41µg/L (range 0.16–43.22µg/L), 4.05µg/L (range, 1.50–12.88µg/L) and 12.17µg/L (range, 1.53–64.87µg/L), respectively. After adjusting for maternal age, infant gender, environmental tobacco smoke during pregnancy and after delivery, Home Observation for Measurement of the Environment Inventory results, and arsenic and mercury levels in cord blood, we found that manganese and lead levels above the 75th percentile had a significant adverse association with the overall (β=−7.03, SE=2.65, P=0.0085), cognitive (β=−8.19, SE=3.17, P=0.0105), and language quotients (β=−6.81, SE=2.73, P=0.0133) of the CDIIT. ConclusionsIn utero exposure to environmental manganese and lead may have an adverse association with neurodevelopment at 2 years of age, and there is an interaction effect between the manganese and lead levels in the cord blood that could aggravate the effect.