Assessment of maternal-fetal status of some essential trace elements in pregnant women in late gestation: relationship with birth weight and placental weight

Association of placental weight at birth with maternal whole blood concentration of heavy metals (cadmium, lead, mercury, selenium, and manganese): The Japan Environment and Children's Study (JECS)

BACKGROUND

Lifelong health is dependent on prenatal growth and development, influenced by the placental intrauterine environment. Charged with dual functions--exchange of oxygen and nutrients as well as a barrier against toxins--the placenta itself is susceptible to environmental exposure to heavy metals.

OBJECTIVE

To examine the use of placenta weight as a biomarker for heavy metal exposure using a large Japanese cohort of pregnant women.

METHODS

The placenta weight, as a biomarker of exposure to heavy metals (cadmium, lead, and mercury), was investigated using data from the Japan Environment and Children's Study (2011-2014). Selenium and manganese were included as factors directly affecting fetal growth or heavy metal toxicity. Maternal blood samples collected in the second or third trimester were used to measure heavy metal concentrations. The association between maternal blood metal concentrations and placenta weight was explored by applying Z scores and multivariable logistic regression analysis and classifying participants into quartiles (Q1, Q2, Q3, and Q4) according to metal concentrations.

RESULTS

This study included a total of 73,005 singleton pregnant women who delivered via live births and met the inclusion criteria. The median heavy metal concentrations in the maternal whole blood were 0.662 ng/g cadmium, 5.85 ng/g lead, 3.61 ng/g mercury, 168 ng/g selenium, and 15.3 ng/g manganese. Regression analysis revealed a significant correlation between placenta weight Z scores and maternal blood metal concentrations: cadmium, 0.0660 (standard error = 0.0074, p < 0.001); selenium, -0.3137 (standard error = 0.0276, p < 0.001); and manganese, 0.1483 (standard error = 0.0110, p < 0.001).

CONCLUSION

This study provides a robust examination of the association between heavy metal exposure and placenta weight. Cadmium and manganese showed a positive correlation with significant differences, whereas selenium showed a negative correlation. Essential elements notably affect placenta weight differently. No significant association was noted between lead or mercury and placenta weight.

Does the Micronutrient Molybdenum Have a Role in Gestational Complications and Placental Health?

Molybdenum is an essential trace element for human health and survival, with molybdenum-containing enzymes catalysing multiple reactions in the metabolism of purines, aldehydes, and sulfur-containing amino acids. Recommended daily intakes vary globally, with molybdenum primarily sourced through the diet, and supplementation is not common. Although the benefits of molybdenum as an anti-diabetic and antioxidant inducer have been reported in the literature, there are conflicting data on the benefits of molybdenum for chronic diseases. Overexposure and deficiency can result in adverse health outcomes and mortality, although physiological doses remain largely unexplored in relation to human health. The lack of knowledge surrounding molybdenum intake and the role it plays in physiology is compounded during pregnancy. As pregnancy progresses, micronutrient demand increases, and diet is an established factor in programming gestational outcomes and maternal health. This review summarises the current literature concerning varied recommendations on molybdenum intake, the role of molybdenum and molybdoenzymes in physiology, and the contribution these play in gestational outcomes.

Examination of Trace Metals and Their Potential Transplacental Transfer in Pregnancy

With the ever-growing concern for human health and wellbeing, the prenatal period of development requires special attention since fetuses can be exposed to various metals through the mother. Therefore, this study explored the status of selected toxic (Pb, Cd, Ni, As, Pt, Ce, Rb, Sr, U) and essential trace metals (Mn, Co, Cu, Zn, Se) in the umbilical cord (UC) sera, maternal sera, and placental tissue samples of 92 healthy women with normal pregnancies. A further aim focuses on the potential transplacental transfer of these trace metals. Based on the obtained levels of investigated elements in clinical samples, it was observed that all of the trace metals cross the placental barrier and reach the fetus. Furthermore, statistical analysis revealed significant differences in levels of toxic Ni, As, Cd, U, Sr, Rb, and essential Mn, Cu, and Zn between all three types of analyzed clinical samples. Correlation analysis highlighted As to be an element with levels that differed significantly between all tested samples. Principal component analysis (PCA) was used to enhance these findings. PCA demonstrated that Cd, Mn, Zn, Rb, Ce, U, and Sr were the most influential trace metals in distinguishing placenta from maternal and UC serum samples. As, Co, and Cu were responsible for the clustering of maternal serum samples, and PCA demonstrated that the Pt level in UC sera was responsible for the clustering of these samples. Overall, the findings of this study could contribute to a better understanding of transplacental transfer of these trace metals, and shed a light on overall levels of metal exposure in the population of healthy pregnant women and their fetuses.

Association of selenium, zinc and copper concentrations during pregnancy with birth weight: A systematic review and meta-analysis

BACKGROUND

Normal fetal growth is associated with maternal nutrition. Trace elements play important roles in fetus growth. This review aims to provide a summary of the literature evaluating the relation between selenium, zinc and copper levels during pregnancy with birth weight.

METHOD

A systematic literature search was conducted in Medline database (PubMed), Scopus, Web of science and Google scholar up to September 2020. Fifty observational studies were included in the final analyses. The desired pooled effect size was considered as standardized mean differences with 95 % CI or correlation. Cochran's Q statistic was used to test the heterogeneity between the included studies (I²).

RESULT

A significant differences were found between pooled standardized mean differences (SMD) of umbilical cord blood copper levels in small-for-gestational age birth weight (SGA) and appropriate-for-gestational age birth weight (AGA) (SMD: 0.34 μg/L, 95 % CI: 0.13 to 0.56). There was a significant pooled correlation between umbilical cord blood selenium concentrations and birth weight (r: 0.08, 95 % CI: 0.01 to 0.16). A significant pooled correlation was found between umbilical cord blood zinc concentrations and birth weight (r: 0.09, 95 % CI: 0.04 to 0.15), with significant heterogeneity (I² % = 0.63). There was significant positive association between maternal blood zinc concentrations and birth weight.

CONCLUSION

Findings showed the association of trace elements including selenium, zinc and copper during pregnancy with birth weight. There was significant correlation between umbilical cord and maternal blood selenium and zinc levels with birth weight. The umbilical cord blood copper levels in SGA birth weight was higher than copper levels in AGA birth weight.

Role of zinc in neonatal growth and brain growth: review and scoping review

This manuscript includes (1) a narrative review of Zinc as an essential nutrient for fetal and neonatal growth and brain growth and development and (2) a scoping review of studies assessing the effects of Zinc supplementation on survival, growth, brain growth, and neurodevelopment in neonates. Very preterm infants and small for gestational age infants are at risk for Zinc deficiency. Zinc deficiency can cause several complications including periorificial lesions, delayed wound healing, hair loss, diarrhea, immune deficiency, growth failure with stunting, and brain atrophy and dysfunction. Zinc is considered essential for oligodendrogenesis, neurogenesis, neuronal differentiation, white matter growth, and multiple biological and physiological roles in neurobiology. Data support the possibility that the critical period of Zinc delivery for brain growth in the mouse starts at 18 days of a 20-21-day pregnancy and extends during lactation and in human may start at 26 weeks of gestation and extend until at least 44 weeks of postmenstrual age. Studies are needed to better elucidate Zinc requirement in extremely low gestational age neonates to minimize morbidity, optimize growth, and brain growth, prevent periventricular leukomalacia and optimize neurodevelopment. IMPACT: Zinc is essential for growth and brain growth and development. In the USA, very preterm small for gestational age infants are at risk for Zinc deficiency. Data support the possibility that the critical period of Zinc delivery for brain growth in the mouse starts at 18 days of a 20-21-day pregnancy and extends during lactation and in human may start at 26 weeks' gestation and extend until at least 44 weeks of postmenstrual age. Several randomized trials of Zinc supplementation in neonates have shown improvement in growth when using high enough dose, for long duration in patients likely to or proven to have a Zinc deficiency. Studies are needed to better elucidate Zinc requirement in extremely low gestational age neonates to minimize morbidity, optimize growth and brain growth, prevent periventricular leukomalacia and optimize neurodevelopment.

Associations between molybdenum exposure and ultrasound measures of fetal growth parameters: A pilot study

Previous studies have suggested the association of molybdenum (Mo) exposure with some adverse outcomes. However, limited epidemiological studies have been performed to explore the association between maternal Mo exposure level and fetal growth. This study recruited 220 pregnant women during their second trimester. The mother's urinary Mo concentration was measured by inductively coupled plasma mass spectrometry (ICP-MS). The fetal biometric parameters, including head circumference (HC), biparietal diameter (BPD), femur diaphysis length (FL), and abdominal circumference (AC) were assessed by prenatal ultrasound. Estimated fetal weight (EFW) was evaluated using the formula of Hadlock. Multivariable linear regression models were applied to estimate the relationships between Mo level and fetal biometric parameters, and potential confounders were adjusted. A one-unit increment in natural-logarithm transformed urinary Mo level was significantly associated with reductions in fetal AC of -0.34 cm (95%CI: -0.63, -0.04), and was negatively related to EFW (β = -18.2, 95%CI: -40.5, 4.2). Furthermore, when participants were stratified by copper (Cu) level, the results showed that the magnitude of negative association between Mo and AC (β = -0.55, 95%CI: -1.13, 0.04) was greater in pregnant women with Cu level below median value, comparing with those with Cu level above median value (β = -0.08, 95%CI: -0.57, 0.42), and a similar pattern was found for EFW, although the interaction between Mo and Cu was not significant. Our data suggested an inverse association of maternal urinary Mo level with fetal AC and EFW during the second trimester of pregnancy. These associations might be stronger in pregnant women with relatively lower Cu levels.

Elemental Metabolomics for Prediction of Term Gestational Outcomes Utilising 18-Week Maternal Plasma and Urine Samples

A normal pregnancy is essential to establishing a healthy start to life. Complications during have been associated with adverse perinatal outcomes and lifelong health problems. The ability to identify risk factors associated with pregnancy complications early in gestation is vitally important for preventing negative foetal outcomes. Maternal nutrition has been long considered vital to a healthy pregnancy, with micronutrients and trace elements heavily implicated in maternofoetal metabolism. This study proposed the use of elemental metabolomics to study multiple elements at 18 weeks gestation from blood plasma and urine to construct models that could predict outcomes such as small for gestational age (SGA) (n = 10), low placental weight (n = 18), and preterm birth (n = 13) from control samples (n = 87). Samples collected from the Lyell McEwin Hospital in Adelaide, South Australia, were measured for 27 plasma elements and 37 urine elements by inductively coupled plasma mass spectrometry. Exploratory analysis indicated an average selenium concentration 20 μg/L lower than established reference ranges across all groups, low zinc in preterm (0.64 μg/L, reference range 0.66-1.10 μg/L), and higher iodine in preterm and SGA gestations (preterm 102 μg/L, SGA 111 μg/L, reference range 40-92 μg/L). Using random forest algorithms with receiver operating characteristic curves, low placental weight was predicted with 86.7% accuracy using plasma, 78.6% prediction for SGA with urine, and 73.5% determination of preterm pregnancies. This study indicates that elemental metabolomic modelling could provide a means of early detection of at-risk pregnancies allowing for more targeted monitoring of mothers, with potential for early intervention strategies to be developed.

Maternal Dietary Selenium Intake during Pregnancy Is Associated with Higher Birth Weight and Lower Risk of Small for Gestational Age Births in the Norwegian Mother, Father and Child Cohort Study

Selenium is an essential trace element involved in the body’s redox reactions. Low selenium intake during pregnancy has been associated with low birth weight and an increased risk of children being born small for gestational age (SGA). Based on data from the Norwegian Mother, Father and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN), we studied the association of maternal selenium intake from diet and supplements during the first half of pregnancy (n = 71,728 women) and selenium status in mid-pregnancy (n = 2628 women) with birth weight and SGA status, according to population-based, ultrasound-based and customized growth standards. An increase of one standard deviation of maternal dietary selenium intake was associated with increased birth weight z-scores (ß = 0.027, 95% CI: 0.007, 0.041) and lower SGA risk (OR = 0.91, 95% CI 0.86, 0.97) after adjusting for confounders. Maternal organic and inorganic selenium intake from supplements as well as whole blood selenium concentration were not associated with birth weight or SGA. Our results suggest that a maternal diet rich in selenium during pregnancy may be beneficial for foetal growth. However, the effect estimates were small and further studies are needed to elucidate the potential impact of selenium on foetal growth.

Association of Cord Blood Zinc Level and Birth Weight in a Sample of Iranian Neonates

Background:

In addition to its short-term effects, low birth weight increases the risk of noncommunicable diseases (NCDs) in adult life. The quality of maternal diet including the macronutrient intake is very important in this regard. This study aims to evaluate the possible associations between maternal zinc and neonatal anthropometric measures.

Method:

This cross-sectional study was conducted on 226 pairs of mothers-neonates in Isfahan, Iran. Maternal characteristics including the history of the disease, age, preconceptional weight, weight gain during pregnancy, as well as, anthropometric characteristics of neonates such as weight, height, length, and circumferences of head, belly, chest, and thigh were documented. Cord blood zinc was measured by atomic absorption spectrophotometer in three groups of neonates depending on their weights.

Results:

The gestational age of neonates was 35 to 38 weeks with a mean weight of 3.13 ± 0.42 kg. The mean of zinc concentration was 0.81 ± 0.18 and it was higher in neonates with appropriate weight than in those with high or low birth weight (0.82 ± 0.18, 0.75 ± 0.19, and 0.65 ± 0.12 ng/ml, respectively). Bivariate correlation analysis showed significant weak correlation between cord blood zinc and neonatal weight (r = 0.16, P = 0.04).

Conclusions:

The cord blood zinc concentration of normal-weight neonates was higher than others. Our findings suggest that maternal zinc may influence neonatal birth weight, and it should be considered in the primordial prevention of NCDs.

High maternal selenium levels are associated with increased risk of congenital heart defects in the offspring

OBJECTIVE

To examine whether maternal hair or cord blood selenium levels are associated with infant congenital heart defects (CHDs).

METHOD

A hospital-based case-control study was performed with samples collected from 2010 to 2014. Selenium levels in maternal hair and fetal cord serum were measured using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Data from medical records of infants with CHDs were collected. Logistic regression analysis was employed to examine the independent association between maternal selenium exposure and fetal CHD.

RESULTS

In total, 888 pregnant women were included in this study. Median (interquartile range) selenium levels in of maternal hair was similar in the control and CHD group. A significant association was detected between increased maternal hair selenium concentration and CHDs in offspring (adjusted odds ratio [aOR] 3.57, 95 %CI, 1.90-6.70). The association was present in all CHD groups, including septal defects, conotruncal defects, left ventricular outflow tract obstruction, right ventricular outflow tract obstruction, and anomalous pulmonary venous return.

CONCLUSION

High maternal selenium level is significantly associated with the occurrence of fetal CHD.

Trace element profiles in pregnant women's sera and umbilical cord sera and influencing factors: Repeated measurements

In utero exposure to toxic heavy metals and deficient or excessive essential trace elements during pregnancy may have adverse effects on pregnant women and their offsprings, which are of great concern. The objective of the present study was to characterize serum concentrations of multiple trace elements at multiple time points during pregnancy in Chinese women. Three thousand four hundred and sixteen pregnant women in total were included from MABC (Ma'anshan Birth Cohort) study. Fasting sera in the morning and questionnaires were obtained at three separate follow-up visits. Nineteen trace elements from serum samples were analyzed, including aluminum (Al), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), barium (Ba), thallium (Tl), lead (Pb), calcium (Ca), magnesium (Mg), mercury (Hg) and molybdenum (Mo). The total detection rates for most elements were 100% rather than Ni (99.98%), As (99.97%), Cd (99.6%), Ba (99.9%), Pb (99.8%), Hg (99.8%). The concentration distributions of 19 elements varied vastly. Median concentrations for all trace elements ranged from 38.5 ng/L to 102.9 mg/L. The moderate interclass correlation coefficients (ICCs) were observed for Co, Cu, Se and Hg, ranging from 0.40 to 0.62; the lower ICCs, ranging from 0.13 to 0.32 were for Fe, Zn, Cd, Ba, Tl, Mg and Mo. The intraclass correlation effects were not observed for the remaining elements, such as Al, V, Cr, Mn, Ni, As and Pb. The concentrations of each element between three time points were significantly different; significant differences were also found between any two time points except for Ni, Cd and Mo. Many factors could affect the levels of trace elements, and a very important factor of them was season. Consequently, a single measurement of elements in sera seems not enough to describe exposure levels throughout pregnancy; additionally, season affected exposure levels of trace elements with moderate ICCs showed certain regularity. Future analyses should take sampling seasons into consideration carefully.

Early pregnancy maternal trace mineral status and the association with adverse pregnancy outcome in a cohort of Australian women

Maternal micronutrient deficiencies in pregnancy can have profound effects on fetal development and pregnancy outcome. Plasma trace minerals including copper, zinc, selenium and iron have been shown to be extremely important in supporting reproduction. We sought to determine whether there is an association between maternal trace mineral status in early pregnancy and pregnancy complications using a prospective cohort study of 1065 pregnant Australian women who were recruited as part of the Screening for Pregnancy Endpoints (SCOPE) study in Adelaide. Copper, zinc, selenium and iron present in the plasma were measured using mass spectrometry in samples collected at 15±1 weeks' gestation. After adjusting for covariates, women with lower plasma copper (<27.9μmol/L and 27.9-32.5μmol/L) had decreased risk for any pregnancy complication when compared with women with high plasma copper (>32.5μmol/L) (aRR=0.87; 95% CI=0.76, 0.99 and aRR=0.88; 95% CI=0.78, 1.00, respectively). This was also observed when adjusting for plasma zinc and selenium status (<27.9μmol/L: aRR=0.81; 95% CI=0.69, 0.96 and 27.9-32.5μmol/L: aRR=0.84; 95% CI=0.72, 0.98). Combined low copper and zinc status was also associated with a reduced risk of any pregnancy complication as compared with high copper and zinc status (aRR=0.80; 95% CI=0.70, 0.93). These results provide justification for further work into elucidating the mechanistic role of trace elements in early pregnancy, as well as their interactions in supporting successful pregnancy outcomes.

Placental transfer and levels of mercury, selenium, vitamin E, and docosahexaenoic acid in maternal and umbilical cord blood

Methylmercury (MeHg) is a neurotoxicant known to affect the developing fetal brain as a sensitive target organ. As most mercury (Hg) in blood is MeHg, total mercury (THg) levels in blood are used to estimate the body burden of MeHg. The nutrients selenium (Se), vitamin E, and docosahexaenoic acid (DHA) are protective against MeHg toxicity. We compared maternal and cord blood concentrations of biochemical substances, THg and Se, vitamin E, DHA, and other elements, fatty acids, and amino acids in 54 Japanese mother-newborn pairs to elucidate the fetal risk of MeHg toxicity. Cord blood had higher hematocrit and amino acid values and lower concentrations of lipid components, including fatty acids compared with maternal blood. THg levels in cord blood (7.26ng/g) were 1.9 times higher than levels in maternal blood (3.79ng/g). Se concentrations in cord blood (176ng/g) were slightly higher than concentrations in maternal blood (156ng/g). Levels of vitamin E (0.31mg/dL) and DHA (58.8μg/mL) in cord blood were much lower than levels in maternal blood (1.38mg/dL and 147μg/mL, respectively). The ratios of Se/THg, vitamin E/THg, and DHA/THg in cord blood were lower than ratios in maternal blood. These results suggest that fetuses are at higher risk to MeHg toxicity.

Selected maternal, fetal and placental trace element and heavy metal and maternal vitamin levels in preterm deliveries with or without preterm premature rupture of membranes

AIM

To compare maternal, fetal and placental trace element (magnesium, zinc and copper) and heavy metal (cadmium and lead) and maternal vitamin (retinol, α [alpha]-tocopherol, vitamin D₃ , 25-hydroxyvitamin D₃ and 1,25-dihydroxyvitamin D₃ ) levels in preterm deliveries with and without preterm premature rupture of membranes (PPROM).

METHODS

Sixty-eight patients giving birth preterm were grouped into preterm deliveries with PPROM (n = 35) and without PPROM (n = 33). Following delivery, maternal and umbilical cord blood sera and placental tissue samples were obtained. While magnesium, zinc, copper, cadmium and lead levels were measured in all samples, the levels of retinol, α-tocopherol, vitamin D₃ , 25-hydroxyvitamin D₃ and 1,25-dihydroxyvitamin D₃ were measured only in maternal serum.

RESULTS

While magnesium level in maternal serum and zinc levels in both maternal and umbilical cord sera were lower, placental magnesium level was higher in preterm deliveries with PPROM (P < 0.01). Umbilical cord serum magnesium, placental tissue zinc and maternal and umbilical cord sera and placental tissue copper, cadmium, and lead levels did not differ between the groups (P > 0.05). In preterm deliveries with PPROM, 25-hydroxyvitamin D₃ and retinol levels were higher, while vitamin D₃ and 1,25-dihydroxyvitamin D₃ levels were lower in maternal serum (P < 0.05). Maternal serum α-tocopherol levels were similar between the groups.

CONCLUSION

Compared to spontaneous preterm births, PPROM is associated with low maternal serum together with high placental tissue magnesium and low maternal and umbilical cord sera zinc levels. Higher retinol and 25-hydroxyvitamin D₃ and lower vitamin D₃ and 1,25-dihydroxyvitamin D₃ maternal serum levels are also evident in these patients.

Levels of Silicon in Maternal, Cord, and Newborn Serum and Their Relation With Those of Zinc and Copper

BACKGROUND

Evidence of silicon's importance to health has been gradually accumulating. Nevertheless, there are few studies comparing serum silicon levels in newborns with maternal levels. Likewise, little is known concerning the inter-relation between silicon and other trace elements.

OBJECTIVE

The present study evaluated maternal and newborn levels of serum silicon and their relation to those of zinc and copper.

METHODS

We measured serum silicon, copper, and zinc in 66 pregnant women, in the umbilical cord of their infants, and in 44 newborns, by atomic absorption spectrophotometry. All the samples were from fasted subjects.

RESULTS

Serum silicon level in term newborns (20.6 ± 13.2 μmol/L) was significantly higher than in umbilical cord (8.9 ± 3.5 μmol/L; P < 0.0001). Mean serum silicon level in maternal vein (7.7 ± 3.4 μmol/L) was lower than that in umbilical cord, although differences were not significant. We also found higher levels of zinc (P = 0.008) and lower levels of copper (P < 0.0001) in cord blood compared with maternal blood. Umbilical venous/maternal venous level ratios of zinc, copper, and silicon were 1.5 ± 0.5, 0.2 ± 0.1, and 1.3 ± 0.7, respectively. There was a positive correlation between silicon and zinc levels (r = 0.32), and a negative correlation between copper and zinc levels (r = -0.35).

CONCLUSIONS

It seems that there is a positive gradient of silicon from the mother to her fetus. Silicon levels were higher in newborn than in cord blood, and correlated significantly with that of zinc but not copper. Additional investigations are needed to further define the role of silicon and its interaction with other trace elements during the perinatal period.

Maternal and Umbilical Cord Blood Levels of Zinc and Copper in Active Labor Versus Elective Caesarean Delivery at Khartoum Hospital, Sudan

A case-control study was conducted in Khartoum Hospital Sudan to determine maternal and umbilical cord blood levels of zinc and copper in active labor versus elective cesarean delivery. Cases were women delivered vaginally and controls were women delivered by elective cesarean (before initiation of labor). Paired maternal and cord zinc and copper were measured using atomic absorption spectrophotometry. The two groups (52 paired maternal and cord in each arm) were well matched in their basic characteristics. In comparison with cesarean delivery, the median (interquartile range) of both maternal [87.0 (76.1-111.4) vs. 76.1 (65.2-88.3) μg/dL, P = 0.004] and cord zinc [97.8 (87.0-114.1) vs. 81.5(65.2-110.2) μg/dL P = 0.034] levels were significantly higher in the vaginal delivery. While there was no significant difference in the maternal copper [78.8 (48.1-106.1) vs. 92.4 (51.9-114.9) μg/dL, P = 0.759], the cord copper [43.5(29.9-76.1) vs. 32.2(21.7-49.6) μg/dL, P = 0.019] level was significantly higher in vaginal delivery. There was no significant correlation between zinc (both maternal and cord) and copper. While the cord zinc was significantly correlated with maternal zinc, there was no significant correlation between maternal and cord copper. The current study showed significantly higher levels of maternal and cord zinc and cord copper in women who delivered vaginally compared with caesarean delivery.

Assessment of ten trace elements in umbilical cord blood and maternal blood: association with birth weight

BACKGROUND

Trace elements are an essential nutritional component for humans and inadequate tissue-concentrations may have a significant effect on fetal size.

OBJECTIVE

To measure ten trace elements in blood samples from mothers and their newborns, and assess their association with anthropometric characteristics at birth. The effects of other factors on fetal growth, such as biologic characteristics of the infant and mother, were analysed.

METHODS

A cross-sectional study was conducted in the Hospital general, University of Valencia, Spain. Healthy pregnant women, and their full-term infants were selected (n = 54 paired samples). Infants were grouped according to birth weight: small for gestational age (SGA n = 11), appropriate (AGA n = 30), and large (LGA n = 13). Anthropometric and biologic characteristics of the infant and mother were recorded. Levels of ten essential elements: arsenic (As), barium (Ba), cobalt (Co), copper (Cu), chrome (Cr), iron (Fe), magnesium (Mg), manganese (Mn), selenium (Se) and zinc (Zn), in maternal and cord plasma samples were determined. Samples were obtained from the umbilical cord immediately after delivery and the samples of their mothers were drawn at 2-4 h after delivery.

RESULTS

The analysis identified that cord blood Cu (p = 0.017) and maternal blood Ba and Mg (p = 0.027 and p = 0.002, respectively) concentrations were significantly higher among SGA infants compared to AGA and LGA infants. A multiple linear regression analysis showed that increased umbilical cord Cu concentration (adjusted β -146.4 g, 95% CI -255 to -37.7; p = 0.009), maternal smoking during pregnancy (adjusted β -483.8 g, 95% CI -811.7 to -155.9; p = 0.005), shorter gestational age (adjusted β 350.1 g, 95% CI 244.5 to 455.8; p = 0.000), and female sex (adjusted β -374 g, 95% CI -648 to -100; p = 0.009) were significantly associated with decreased birth weight. Maternal anaemia was positively associated with birth weight (adjusted β 362 g, 95% CI 20.8 to 703.1; p = 0.038). No significant associations were found between maternal trace elements and birth weight in multivariate analysis.

CONCLUSIONS

We did not observe significant associations of cord blood trace elements other than Cu and maternal trace elements with birth weight in the multivariate analyses.

Blood zinc, iron, and copper levels in critically ill neonates

The aim of this study is to explore the prognostic value of blood zinc, iron, and copper levels in critically ill neonates by comparing blood metal levels with the score for neonatal acute physiology (SNAP). Forty-six neonates (26 boys, 20 girls; ages ranging from 10 min to 23 days) who had been admitted to the neonatal intensive care unit of hospital and who were critically ill according to SNAP were included. Another 15 neonates (12 boys, 8 girls; ages ranging from 30 min to 24 days) who were brought to the hospital for a health checkup were included as controls. Clinical data, time in the intensive care unit, prognosis, and SNAP for critically ill neonates were recorded. Blood Cu, Zn, and Fe values were measured by inductively coupled plasma atomic emission spectrophotometry. Ill neonates were divided into extremely critical (SNAP ≥ 10) and critical groups (1 ≤ SNAP < 9). Zn levels were lower in patients than in controls (p <0.05). Cu levels did not differ between patients and controls (p >0.05). Fe levels were not significantly between the critical and control groups (p >0.05). In ill neonates, blood Zn and Fe concentrations in the extremely critical group were lower than in the critical group (p <0.05). Serious illness in neonates may lead to decreased Zn and Fe blood concentrations. Zn and Fe supplements may be beneficial for critically ill children.

Manganese and selenium concentrations in umbilical cord serum and attention deficit hyperactivity disorder in childhood

Existing evidence on the effects of manganese and selenium during fetal life on neurodevelopmental disorders is inadequate. This study aims to investigate the hypothesized relationship between fetal exposure to manganese and selenium and attention deficit hyperactivity disorder (ADHD) diagnosis in childhood. Children born between 1978 and 2000 with ADHD (n=166) were identified at the Department of Child and Adolescent Psychiatry in Malmö, Sweden. Controls from the same region (n=166) were selected from the Medical Birth Register and were matched for year of birth and maternal country of birth. Manganese and selenium were measured in umbilical cord serum. The median cord serum concentrations of manganese were 4.3μg/L in the cases and 4.1μg/L in the controls. The corresponding concentrations of selenium were 47 and 48μg/L. When the exposures were analyzed as continuous variables no associations between cord manganese or selenium concentration and ADHD were observed. However, children with selenium concentrations above the 90th percentile had 2.5 times higher odds (95% confidence interval 1.3-5.1) of having ADHD compared to those with concentrations between the 10th and 90th percentiles. There was no significant interaction between manganese and selenium exposure (p=0.08). This study showed no association between manganese concentrations in umbilical cord serum and ADHD. The association between ADHD diagnoses in children with relatively high cord selenium was unexpected and should be interpreted with caution.

Selenium status in U.K. pregnant women and its relationship with hypertensive conditions of pregnancy

Dietary intake/status of the trace mineral Se may affect the risk of developing hypertensive conditions of pregnancy, i.e. pre-eclampsia and pregnancy-induced hypertension (PE/PIH). In the present study, we evaluated Se status in U.K. pregnant women to establish whether pre-pregnant Se status or Se supplementation affected the risk of developing PE/PIH. The samples originated from the SPRINT (Selenium in PRegnancy INTervention) study that randomised 230 U.K. primiparous women to treatment with Se (60 μg/d) or placebo from 12 weeks of gestation. Whole-blood Se concentration was measured at 12 and 35 weeks, toenail Se concentration at 16 weeks, plasma selenoprotein P (SEPP1) concentration at 35 weeks and plasma glutathione peroxidase (GPx3) activity at 12, 20 and 35 weeks. Demographic data were collected at baseline. Participants completed a FFQ. U.K. pregnant women had whole-blood Se concentration lower than the mid-range of other populations, toenail Se concentration considerably lower than U.S. women, GPx3 activity considerably lower than U.S. and Australian pregnant women, and low baseline SEPP1 concentration (median 3.00, range 0.90-5.80 mg/l). Maternal age, education and social class were positively associated with Se status. After adjustment, whole-blood Se concentration was higher in women consuming Brazil nuts (P= 0.040) and in those consuming more than two seafood portions per week (P= 0.054). A stepwise logistic regression model revealed that among the Se-related risk factors, only toenail Se (OR 0.38, 95% CI 0.17, 0.87, P= 0.021) significantly affected the OR for PE/PIH. On excluding non-compliers with Se treatment, Se supplementation also significantly reduced the OR for PE/PIH (OR 0.30, 95% CI 0.09, 1.00, P= 0.049). In conclusion, U.K. women have low Se status that increases their risk of developing PE/PIH. Therefore, U.K. women of childbearing age need to improve their Se status.

Zinc and copper levels in low birth weight deliveries in Medani Hospital, Sudan

Background

Low birth weight (LBW) is a worldwide health problem, especially in developing countries. We conducted a case–control study at Medani Hospital, Sudan. Cases were women who delivered a LBW (<2500 g) newborn and consecutive women who delivered a normal weight (>2500 g) newborn were controls. Questionnaires were used to collect clinical data. Zinc and copper levels were measured by an atomic absorption spectrophotometer.

Findings

The two groups (50 in each arm) were well matched in their basic characteristics. Median (25–75th interquartile range) maternal zinc (62.9 [36.3–96.8] vs. 96.2 [84.6–125.7] μg/dl; P <0.001) and copper (81.6 [23.7–167.5] vs. 139.8 [31.9–186.2] μg/dl; P = 0.04) levels were significantly lower in cases than in controls. Cord copper levels in cases were significantly lower than those in controls (108 [55.1–157.9] vs. 147.5 [84.5–185.2] μg/dl; P = 0.02). There were significant direct correlations between birth weight and maternal copper levels and maternal and cord zinc levels.

Conclusions

Maternal zinc and copper levels, as well as cord copper levels, are lower in LBW newborns than in those with normal weight.

Serum selenium levels of the very low birth weight premature newborn infants with bronchopulmonary dysplasia

BACKGROUND

The selenium (Se) is an essential trace element that has a critical role in synthesis and activity of a number of selenoproteins with protective properties against free radical damage. This study was conducted to detect the serum Se concentration in very low birth weight (VLBW) preterm infants and its association with bronchopulmonary dysplasia (BPD).

MATERIALS AND METHODS

Cord blood Se concentration was determined in 54 neonates with gestation age 30 week or less. Another sample was obtained from these infants at day 28 of birth and serum Se levels were measured by atomic absorption spectrophotometer. All neonates were followed for oxygen dependency at 28 day after birth and 36 week postmenstrual age.

RESULTS

The mean cord blood Se concentration in studied neonates was 64.78 ± 20.73 μgL(-1). Serum Se concentration was 60.33 ± 26.62 μgL(-1) at age 28-day. No significant correlation was observed for serum Se concentration at birth and at one month after birth (r = -0.04, p = 0.72). BPD was diagnosed in 25 neonates (46%). The mean serum Se concentration at one month was 57.16 ± 29.68 μgL(-1) in patients with BPD (25 cases) and 63.27 ± 23.6 μgL(-1) in 29 patients without BPD (p = 0.40).

CONCLUSION

In our study, serum Se concentration at 28 day of birth was lower than cord blood levels in preterm neonates, but we have not found significant difference among patients who had BPD or not with respect to serum Se concentrations at this age.

Different levels of prenatal zinc and selenium had different effects on neonatal neurobehavioral development

Either deficient or excessive of essential nutrients had adverse effects. Effects of different levels of prenatal zinc (Zn) and selenium (Se) on fetal neurobehavioral development remain unclear. To determine the effects of different cord serum levels of Zn and Se on neurobehavioral development in neonates and to explore possible threshold level of Zn and Se based on fetal neurodevelopment, we conducted this epidemiological research. In the multi-center study, we investigated these questions in 927 mother-newborn pairs in Shanghai, China, from 2008 through 2009. Umbilical cord serum concentrations of Zn and Se were measured and Neonatal Behavioral Neurological Assessment (NBNA) tests were conducted. The median cord serum Zn and Se concentrations were 794.3 μg/L and 63.1 μg/L, respectively. A nonlinear relationship was observed between cord serum Zn and NBNA after adjusting for potential confounders. NBNA score decreased with increasing Zn levels after 794.3 μg/L (adjusted β=-3.0, 95% CI: -3.6 to -2.4, p<0.001). Additionally, an invert U-shape with a threshold Se of 100 μg/L was observed between cord serum Se and NBNA. The adjusted regression coefficient was 4.4 (95% CI: 3.6-5.2, p<0.001) for Se<100 μg/L while -3.6 (95% CI: -6.1 to -1.1, p<0.01) for Se≥100 μg/L. Of the 927 infants, 50% had a high level Zn (≥794.3 μg/L) and 8.6% had a high level Se (≥100 μg/L). High levels of both Zn and Se mainly had adverse effects on behavior and passive tone (p<0.001). Taken together, our study suggested that a threshold of cord blood Zn and Se was existed for fetal neurodevelopment and the prevalence of excessive Zn was high. Thus, the supplementation of Zn during pregnancy should be considered with caution in Shanghai, China.

Prion protein expression and functional importance in developmental angiogenesis: role in oxidative stress and copper homeostasis

AIM

It has been convincingly shown that oxidative stress and toxicity by deregulated metals, such as copper (Cu), are tightly linked to the development of pre-eclampsia and intrauterine growth retardation (IUGR), the most threatening pathologies of human pregnancy. However, mechanisms implemented to control these effects are far from being understood. Among proteins that bind Cu and insure cellular protection against oxidative stress is the cellular prion protein (PrP(C)), a glycosyl phosphatidyl inositol-anchored glycoprotein, which we reported to be highly expressed in human placenta. Herein, we investigated the pathophysiological role of PrP(C) in Cu and oxidative stress homeostasis in vitro using human placenta and trophoblast cells, and in vivo using three strains of mice (C57Bl6, PrP(C) knockout mice [PrP(-/-)], and PrP(C) overexpressing mice [Tga20]).

RESULTS

At the cellular level, PrP(C) protection against oxidative stress was established in multiple angiogenic processes: proliferation, migration, and tube-like organization. For the animal models, lack (PrP(-/-)) or overexpression (Tga20) of PrP(C) in gravid mice caused severe IUGR that was correlated with a decrease in litter size, changes in Cu homeostasis, increase in oxidative stress response, development of hypoxic environment, failure in placental function, and maintenance of growth defects of the offspring even 7.5 months after delivery.

INNOVATION

PrP(C) could serve as a marker for the idiopathic IUGR disease.

CONCLUSION

These findings demonstrate the stress-protective role of PrP(C) during development, and propose PrP(C) dysregulation as a novel causative element of IUGR.

Maternal weight and body composition during pregnancy are associated with placental and birth weight in rural Bangladesh

Placental growth is a strong predictor of fetal growth, but little is known about maternal predictors of placental growth in malnourished populations. Our objective was to investigate in a prospective study the associations of maternal weight and body composition [total body water (TBW) estimated by bioelectrical impedance and fat and fat-free mass derived from upper arm fat and muscle areas (UAFA, UAMA)] and changes in these with placental and birth weights. Within a cluster-randomized trial of maternal micronutrient supplementation, a subsample of 350 women was measured 3 times across gestation. Longitudinal analysis was used to examine independent associations of ∼10-wk measurements and ∼10-20 wk and ∼20-32 wk changes with birth outcomes. Weight, TBW, and UAMA, but not UAFA, at ∼10 wk were each positively and independently associated with placental weight and birth weight (P < 0.05). Of the maternal ∼10-20 wk changes in measurements, only TBW change and placental weight, and maternal weight and birth weight were positively associated (P < 0.05). Gains in weight, TBW, and UAMA from 20 to 32 wk were positively and UAFA gain was negatively associated with placental weight (P ≤ 0.01). Gains in weight and UAMA from 20 to 32 wk were positively associated with birth weight (P ≤ 0.01). Overall, higher maternal weight and measures of fat-free mass at ∼10 wk gestation and gains from 20 to 32 wk are independently associated with higher placental and birth weight.

Changes in body burden of mercury, lead, arsenic, cadmium and selenium in infants during early lactation in comparison with placental transfer

The developing brains of both fetuses and infants are susceptible to environmental contaminants. However, the contribution of breast-feeding to the element body burden in infants remains unclear. The main objective of this study was to investigate the changes in body burden of elements such as methylmercury, lead, arsenic, cadmium, and selenium in infants during a 3-month breast-feeding period compared with placental transfer of the elements. Element concentrations were measured in maternal and umbilical cord (fetus) red blood cells (RBCs) at parturition and in infant RBCs at 3 months. Most of the mercury in RBCs is in the methyl form, and the total mercury concentration in RBCs reflects methylmercury exposure. The mercury level in cord RBCs was approximately 1.5 times higher than that in mothers, while in infants, it declined by approximately 60% after 3-months' breast-feeding. The cord selenium level was similar to the maternal level, but declined approximately 75% after 3-months' breast-feeding in infants. Lead and arsenic concentrations in cord RBCs were about 60% of the maternal levels, and remained constant until the 3-month study period. The cadmium level in cord RBCs was about 20% of that in maternal RBCs, and remained almost constant until the end of the 3-month study period. In conclusion, although pregnant women should pay attention to avoid high methylmercury exposure, element exposure through breast-feeding does not pose any great concern in this population.

Recent evidence from epidemiological studies on methylmercury toxicity

More than fifty years have passed since the outbreak of Minamata disease, and large-scale methylmercury poisoning due to industrial effluents or methylmercury-containing fungicide intoxication has scarcely happened in developed countries. On the other hand, widespread environmental mercury contamination has occurred in gold and mercury mining areas of developing countries. In this article, we provided an overview of recent studies addressing human health effects of methylmercury, which we searched using the PubMed of the US National Library of Medicine. The following suggestions were obtained for low-level methylmercury exposure: (1) In recent years, the proportion of human studies addressing methylmercury has tended to decrease. (2) Prenatal exposure to methylmercury through fish intake, even at low levels, adversely affects child development after adjusting for polychlorinated biphenyls and maternal fish intake during pregnancy, whereas maternal seafood intake has some benefits. (3) Long-term methylmercury exposure through consumption of fish such as bigeye tuna and swordfish may pose a potential risk of cardiac events involving sympathovagal imbalance. (4) In measuring methylmercury levels in preserved umbilical cord collected from inhabitants born in Minamata areas between 1945 and 1989, the elevated concentrations (≥1 mg/g) were observed mainly in inhabitants born between 1947 and 1968, and the peak coincided with the peak of acetaldehyde production in Minamata. (5) Since some developing countries appear to be in similar situations to Japan in the past, attention should be directed toward early recognition of a risky agent and precautions should be taken against it.

Effects of the interleukin-6 (IL-6) polymorphism on toxic metal and trace element levels in placental tissues

The placenta is a crucial organ of fetal origin that functions in providing nutrients to the fetus from the mother. During pregnancy, the need for essential micronutrients, such as Fe and Zn, increases due to the requirements of the growing fetus. Maternal Fe deficiency induces an increase in Cu levels and can also affect cytokine levels in the placenta. On the other hand, Cu deficiency, although not as common, can also have destructive effects on the fetus. Interleukin-6 (IL-6) is a pleiotropic cytokine with a wide range of biological activities, including such as immune responses, acute-phase reactions, and inflammation. The placenta produces a significant amount of IL-6 during pregnancy. The effects of the IL-6 -174 G/C single nucleotide polymorphism (SNP) on IL-6 gene transcription and on plasma cytokine levels were assessed in the present study. We investigated the association between the IL-6 -174 G/C polymorphism and trace element/toxic metal levels in placental tissues. For the purposes of this study, 95 healthy volunteers were evaluated. Presence of the IL-6 polymorphism was determined using the standard polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique, and metal levels were analyzed by atomic absorption spectrometry (AAS). Based on our data, there were no significant associations between the IL-6 -174 G/C polymorphism and Pb, Cd, Fe, or Zn levels in the placental tissues (p>0.05), but a statistically significant association was detected between the polymorphism and Cu levels (p=0.016). We determined that the mean Cu levels in the placental tissues from individuals with GG, GC and CC genotypes were 5.62±1.98, 6.22±3.22 and 8.00±1.32 ppm, respectively, whereas the overall mean Cu level from the placental tissues was 5.98±2.51 ppm.

Severe pre-eclampsia is associated with abnormal trace elements concentrations in maternal and fetal blood

OBJECTIVE

The study was aimed to compare trace elements concentrations in women with and without severe pre-eclampsia (PE).

METHODS

A prospective case-control study was conducted comparing 43 parturients with severe PE (who received magnesium sulfate [MgSO4]) and 80 healthy parturients and their newborns, matched for gestational age and mode of delivery. Inductively coupled plasma mass spectrometry (ICPMS) was used for the determination of zinc (Zn), copper (Cu), selenium (Se) and magnesium (Mg) levels in maternal as well as arterial and venous umbilical cord serum.

RESULTS

Zn levels (µg/L) were significantly higher in fetal arterial and venous blood of the PE group (947.3 ± 42.5 vs. 543.1 ± 226, 911.1 ± 220.2 vs. 422.4 ± 145, p < 0.001; respectively). Se levels (µg/L) were significantly lower in maternal and fetal arterial and venous cord blood of the PE group (98.6 ± 24.2, 110.7 ± 19.4, 82 ± 17.8 vs. 111.6 ± 17.6, 82.1 ± 17.4 vs. 107.1 ± 25.7, p < 0.001; respectively). Cu levels (µg/L) were significantly lower in fetal arterial and venous cord blood (581.6 ± 367.4 vs. 949 ± 788.8, p = 0.022, 608.3 ± 418.1 vs. 866.9 ± 812.6, p = 0.001 respectively) but higher in maternal blood (2264.6 ± 751.7 vs. 1048 ± 851.1, p < 0.001). These differences remained significant while controlling for the mode of delivery. Mg levels were significantly higher in the PE group as compared with the control group.

CONCLUSIONS

Severe PE is associated with abnormal concentrations of Zn, Cu and Se. Therefore, trace elements may have a crucial role in the pathogenesis of severe PE.

Status of toxic metals in biological samples of diabetic mothers and their neonates

The mechanism of transport of trace elements from the mother to the newborn is still not well known. The aim of present study was to compare the status of trace toxic elements, arsenic (As), cadmium (Cd), and lead (Pb) in biological samples (whole blood, urine and scalp hair) of insulin-dependent diabetic mothers (age ranged 30-40) and their newly born infants (n = 76). An age and socioeconomics matched 68 nondiabetic mothers and their infants, residing in the same locality, who were selected as referents. The elemental concentrations in all three biological samples were determined by an electrothermal atomic absorption spectrometer, prior to microwave-assisted acid digestion. The mean values of As, Cd, and Pb in all biological samples of diabetic mothers and their infants were significantly higher as compared to the referent mother-infant pair samples (p < 0.01). The high levels of As, Cd, and Pb in biological samples of diabetic women may play a role in the pathogenesis of diabetes mellitus and impacts on their neonates.

Trace elements' concentrations in maternal and umbilical cord plasma at term gestation: a comparison between active labor and elective cesarean delivery

OBJECTIVE

Trace elements are minerals required in minute quantities to maintain proper physical functioning. The role of trace elements in the process of parturition is poorly understood. This study was aimed to determine levels of trace elements' concentration in maternal plasma and umbilical venous and arterial plasma at term during active labor vs elective cesarean delivery (CD).

STUDY DESIGN

A prospective case-control study was conducted. Forty healthy parturients in active labor at term with their newborns were compared to 40 healthy parturients matched for maternal age, parity, and gestational age, who delivered by elective CD (before commencement of labor). Samples of maternal venous blood and umbilical cord arterial and venous blood were drawn immediately following delivery. Trace elements' concentrations were measured using the inductively coupled plasma mass spectrometer (ICP-MS).

RESULTS

Significant higher levels of manganese (Mn) and selenium were found in maternal venous plasma during active labor vs elective CD. Magnesium (Mg) levels were significantly higher in maternal venous blood during elective CD compared to active labor. Umbilical cord artery levels of Mg, Mn, and zinc (Zn) were significantly higher in active term labor vs elective CD. Also, significant higher levels of copper and Zn were found in umbilical cord vein between active labor and elective CD.

CONCLUSION

Trace elements' concentrations differ significantly in fetal blood during active labor vs elective CD. Hence, trace elements may play a crucial role in the process of human parturition.

Mercury and heavy metal profiles of maternal and umbilical cord RBCs in Japanese population

Mercury (Hg) and other heavy metal profiles, namely, lead (Pb), arsenic (As), cadmium (Cd), and selenium (Se) were investigated in maternal and umbilical cord (cord) red blood cells (RBCs) at parturition in Japanese population. Correlation coefficients of Hg, Pb, As, Cd, and Se between maternal and cord RBCs were 0.91, 0.79, 0.89, 0.31, and 0.76, respectively, and the respective means of cord/maternal RBCs ratios were 1.63, 0.52, 0.62, 0.12, and 1.18. These results indicate that fetal exposure to these metals (excluding Cd) strongly reflected each maternal exposure level. Among these metals, the placental transfer of methylmercury (MeHg) seemed to be extremely high but that of Cd to be limited. Hg showed positive correlations with Se in maternal RBCs but not in cord RBCs, and the Se/Hg molar ratio was lower in the latter, suggesting that the protective effects of Se against MeHg are less expected in fetuses than in mothers.

Assessment of trace element concentration distribution in human placenta by wavelength dispersive X-ray fluorescence: effect of neonate weight and maternal age

Trace element status in human placenta is dependent on maternal-neonatal characteristics. This work was undertaken to investigate the correlation between essential trace element concentrations in the placenta and maternal-neonatal characteristics. Placenta samples were collected from total 61 healthy mothers at gestation between 37 and 41 weeks. These samples were investigated with the restriction that the mother's age was 20-40 years old and the neonate's weight was 1-4kg. Percent concentrations of trace elements were determined using wavelength dispersive X-ray fluorescence (WDXRF). The placenta samples were prepared and analyzed without exposure to any chemical treatment. Concentrations of Fe, Cu and Zn in placenta tissues were found statistically to vary corresponding to the age of the mother and weight of the neonate. In the subjects, the concentration of Fe and Cu were increased in heavier neonates (p<0.05) and the concentration of Zn was increased with increasing mother age (p<0.05). Consequently, the Fe, Cu and Zn elements appear to have interactive connections in human placenta.

The placenta as a barrier for toxic and essential elements in paired maternal and cord blood samples of South African delivering women

Environmental toxicants such as metals may be detrimental to foetus and infant development and health because of their physiological immaturity, opportunistic and differential exposures, and a longer lifetime over which disease, initiated during pregnancy and in early life, can develop. The placental mechanisms responsible for regulation of absorption and excretion of elements during pregnancy are not fully understood. The aim of this paper is to assess the correlation for selected toxic and essential elements in paired whole blood samples of delivering women and cord blood, as well as to evaluate the placental permeability for selected elements. Regression analyses used to assess this correlation in 62-paired samples of maternal and cord whole blood of delivering women show that the concentrations of mercury, lead, cobalt, arsenic and selenium in maternal and cord blood differed statistically. Lead, cobalt, arsenic and selenium appear to pass the placental barrier by a diffusion mechanism. It was also found that the mercury levels in cord blood were almost double those of the mother, suggesting that the foetus may act as a filter for the maternal mercury levels during pregnancy. Transplacental transfer for arsenic and cobalt was 80% and 45%, respectively, suggesting that the placenta modulates the rate of transfer for these elements. Cadmium, manganese, copper and zinc levels did not show statistically significant correlations between two compartments (maternal versus cord whole blood). The study confirms that most of the toxic metals measured have an ability to cross the placental barrier.

Status of essential trace metals in biological samples of diabetic mother and their neonates

OBJECTIVE

There is accumulating facts that the metabolism of essential trace elements is altered in diabetic patients. The aim of present study was to compare the status of essential trace elements, chromium (Cr), manganese (Mn), and zinc (Zn) in biological samples (whole blood, urine and scalp hair) of insulin dependent diabetic mothers (age ranged 30-40) and their newly born infants (n = 76). An age matched 68 non-diabetic mothers and their infants, residing in the same locality, were selected as referents. For a comparative study, the biological samples of non-diabetic and diabetic pregnant and non pregnant of same age group and socio-economics status were also analysed.

METHODOLOGY

The biological samples (scalp hair, blood and urine) were collected from study and referent groups. The Cr, Mn and Zn concentrations in all three biological samples were determined by a flame/electrothermal atomic absorption spectrometer, prior to microwave assisted acid digestion. The validity and accuracy of the methodology was checked by certified reference materials (CRMs) and using conventional wet acid digestion method on same CRMs.

RESULTS

The mean values of Cr, Mn and Zn in scalp hair and blood samples of diabetic mothers and their infants were significantly lower as compared to the referent mothers-infants pairs (p < 0.01), while urinary excretion of all these elements were high in diabetic mother-infant pair samples.

CONCLUSION

The deficiencies of essential trace elements, Cr, Mn and Zn in biological samples of diabetic women, may play role in the pathogenesis of diabetes mellitus and impacts on their neonates.