Gestational Weight Gain and Exposure of Newborns to Persistent Organic Pollutants

Background: Exposure to persistent organic pollutants (POPs) during fetal development can increase the risk of adverse health effects during childhood. Maternal characteristics and physiological changes during gestation, such as gestational weight gain (GWG), may have an influence in the overall burden of POPs in neonates. However, the associations between GWG and POP concentrations are still not well established.Objective: We examined the association of GWG with cord serum POPs concentrations after adjusting for prepregnancy maternal body mass index (BMI) and other potential determinants of the transfer of POPs into newborns. The GWG values were evaluated after grouping by the reference guidelines of the Institute of Medicine (IOM).Methods: We measured levels of 14 organochlorine pesticides, 7 polychlorobiphenyls (PCBs), and 14 polybrominated diphenyl ethers (PBDEs) in 325 cord serum samples from a Spanish birth cohort. Multivariable models were used to estimate associations of GWG, prepregnancy BMI, and other maternal determinants on cord serum concentrations of POPs.Results: Neonatal concentrations of POPs were inversely associated with GWG after adjustment for age, prepregnancy BMI, educational level, and fish consumption. On average, neonates of women with IOM-recommended GWG have lower POP concentrations than do neonates of mothers with inadequate GWG.Conclusions: The present findings suggest an association between neonatal exposure to POPs and inadequate GWG during pregnancy. Encouraging pregnant women to meet the recommended IOM guidelines for GWG may reduce the accumulation of POPs in newborns.Citation: Vizcaino E, Grimalt JO, Glomstad B, Fernández-Somoano A, Tardón A. 2014. Gestational weight gain and exposure of newborns to persistent organic pollutants. Environ Health Perspect 122:873–879; http://dx.doi.org/10.1289/ehp.1306758     

Toxicokinetic Modeling of Persistent Organic Pollutant Levels in Blood from Birth to 45 Months of Age in Longitudinal Birth Cohort Studies

Background: Despite experimental evidence that lactational exposure to persistent organic pollutants (POPs) can impact health, results from epidemiologic studies are inconclusive. Inconsistency across studies may reflect the inability of current methods to estimate children’s blood levels during specific periods of susceptibility.Objectives: We developed a toxicokinetic model to simulate blood POP levels in children from two longitudinal birth cohorts and aimed to validate it against blood levels measured at 6, 16, and 45 months of age.Methods: The model consisted of a maternal and a child lipid compartment connected through placental diffusion and breastfeeding. Simulations were carried out based on individual physiologic parameters; duration of breastfeeding; and levels of POPs measured in maternal blood at delivery, cord blood, or breast milk. Model validity was assessed through regression analyses of simulated against measured blood levels.Results: Simulated levels explained between 10% and 83% of measured blood levels depending on the cohort, the compound, the sample used to simulate children’s blood levels, and child’s age when blood levels were measured. Model accuracy was highest for estimated blood POP levels at 6 months based on maternal or cord blood levels. However, loss in model precision between the 6th and the 45th month was small for most compounds.Conclusions: Our validated toxicokinetic model can be used to estimate children’s blood POP levels in early to mid-childhood. Estimates can be used in epidemiologic studies to evaluate the impact of exposure during hypothesized postnatal periods of susceptibility on health.     

Occurrence and transport of synthetic musks in paired maternal blood,umbilical cord blood,and breast milk

Although early exposure to environmental pollutants may have important toxicological consequences, the mechanisms of transplacental transfer of synthetic musks are still not well understood. The objective of the present study was to learn the musk contaminations in three matrices, including maternal blood, umbilical cord blood, and breast milk; and investigate their placental transfer mechanisms.The concentrations of eight commonly used synthetic musks were measured in 42 paired samples (126 individual samples in total) of maternal serum, umbilical cord serum, and breast milk from Chinese women living in Shanghai.Musks were ubiquitously detected, especially galaxolide (HHCB) and musk xylene (MX). The total lipid-based concentrations were higher in umbilical cord sera (87.3 ng/g), but lower in breast milk (35.2 ng/g), compared with maternal serum concentrations (71.2 ng/g). There were significant correlations between maternal serum concentrations of HHCBs (HHCB and HHCB-lactone) and umbilical cord serum concentrations, and between maternal serum concentrations and breast milk concentrations (Spearman's rho = 0.338–0.597, p < 0.05), when outliers are excluded. The average transfer ratios of HHCB and HHCB-lactone between maternal sera and umbilical cord sera were >1. And the HHCB-lactone/HHCB ratio in maternal sera was higher compared with umbilical cord sera.Contamination levels were low compared with other regions and HHCBs were found to be the predominant constituents. No regional differences or age-related accumulations were observed. Our study suggests that prenatal exposure to HHCBs occurs and that transplacental transfer is the main route of exposure. Preferential accumulation in umbilical cord blood was observed. The results showed that transplacental transfer of HHCB did not correspond to passive diffusion since the transfer ratios were significantly different from 1. The transfer ratio for HHCB was also larger than that of HHCB-lactone, although HHCB has higher lipid solubility. Low fetal metabolism of HHCB was suggested by the HHCB-lactone/HHCB ratio in maternal and umbilical cord blood.     

Usefulness of umbilical cord mercury concentrations as biomarkers of fetal exposure to methylmercury

In epidemiological studies on the health effect of methylmercury (MeHg) exposure, maternal-hair mercury concentration has been used as an exposure biomarker because of its ease of collection and capability to recapture the exposure history. However, artificial hair-waving reduces the mercury concentration and there is little agreement about which part of the hair strand properly represents fetal exposure. We presented an overview of the studies addressing umbilical cord and mercury in PubMed and evaluated the usefulness of umbilical cord mercury concentrations as biomarkers of fetal exposure to MeHg. The mean total mercury (T-Hg) concentration in cord blood was between 0.5 and 35.6microg/l, and the cord blood-to-maternal blood ratio of T-Hg concentrations was estimated to be approximately 1.5. MeHg concentrations in dried cord tissue did not exceed 0.4 microg/g in Japanese populations without particular exposure to MeHg. Dried cord tissue appeared to be better than wet tissue because the definition of wet weight of the umbilical cord is ambiguous. Both cord-blood and cord-tissue mercury concentrations seemed to correlate closely with maternal-hair and maternal-blood ones. Since cord mercury concentrations are a direct exposure biomarker of the fetus and the cord blood-to-maternal blood ratio of mercury differed markedly among mother-child pairs, mercury concentration in cord blood or dried cord tissue should therefore be used in assessing the possible effects of fetal exposure to MeHg on the susceptible brain. Further studies are required to clarify at which period of exposure during gestation the cord mercury concentration represents in relation to mercury concentrations in maternal segmental hair.     

Specific factors for prenatal lead exposure in the border area of China

The objectives of this study are to examine the prevalence of increased blood lead concentrations in mothers and their umbilical cords, and to identify risk factors for prenatal lead exposure in Kunming city, Yunnan province, China. The study was conducted at two obstetrics departments, and 100 peripartum women were enrolled. The mean blood lead concentrations of the mothers and the umbilical cords were 67.3microg/l and 53.1microg/l, respectively. In multiple linear regression analysis, maternal occupational exposure, maternal consumption of homemade dehydrated vegetables and maternal habitation period in Kunming city were significantly associated with an increase of umbilical cord blood lead concentration. In addition, logistic regression analysis was used to assess the association of umbilical cord blood lead concentrations that possibly have adverse effects on brain development of newborns with each potential risk factor. Maternal frequent use of tableware with color patterns inside was significantly associated with higher cord blood lead concentration in addition to the three items in the multiple linear regression analysis. These points should be considered as specific recommendations for maternal and fetal lead exposure in this city.     

Placental transfer of cadmium in pregnant women

To clarify the maternal-fetal transfer of cadmium across the placenta, cadmium was determined in 21 paired samples of maternal blood, placenta and umbilical cord blood obtained at delivery from pregnant women who did not smoke and had no particular exposure to cadmium compounds in their history. Cadmium was detected in all the samples. In both maternal blood and umbilical cord blood, the cadmium concentrations in the red blood cells were remarkably higher than those in the plasma. The cadmium concentration in the umbilical cord blood was significantly lower than that in the maternal blood, suggesting that the placenta might effectively block the transfer of cadmium to fetuses in pregnant women. The placental cadmium concentration was the highest in the samples determined. The ratios of placental to maternal blood cadmium concentration were very large, indicating that cadmium preferentially accumulates in the placental tissues. On the other hand, the ratios of umbilical cord blood to placental cadmium concentration were very small, indicating that the placenta constitutes an effective barrier against cadmium; that is, the placental cadmium is hard to transfer to fetuses in pregnant women. The significantly positive correlations between maternal blood and placenta, between placenta and umbilical cord blood and between maternal blood and umbilical cord blood in terms of the concentrations of cadmium suggest that the amount of cadmium accumulated in placenta and transferred from mother to fetus is strongly influenced by the cadmium body burden of the mother.     

Low molecular weight plasma antioxidants and lipid peroxidation in maternal and cord blood

OBJECTIVE: To determine the concentrations of the low molecular weight antioxidants urate, bilirubin, albumin and sulphydryl groups and to measure lipid peroxidation levels in pair-matched maternal and cord blood plasma. DESIGN: Venous blood plasma concentrations of urate, bilirubin, albumin and sulphydryls were determined in healthy pregnant women and in pair matched umbilical cords. The ability of maternal and cord plasma to withstand Cu2+-induced lipid peroxidation was assessed by measuring the production of thiobarbituric acid reactive substances (TBARS) over time in plasma incubated with Cu2+. SUBJECTS: Forty healthy women, between 10 and 20 weeks gestation, were recruited randomly from an antenatal clinic. Venous blood samples were obtained from the mothers at the recruitment stage and from the umbilical cords of their newborn after delivery. RESULTS: Urate, bilirubin and sulphydryls were present in significantly higher concentrations (P<0.001) in cord plasma than in maternal plasma. Albumin levels were similar in mothers and cords. Significantly lower levels (P=0.018) of TBARS were produced in cord plasma compared with maternal plasma following incubation with Cu2+. There were significant correlations between albumin and sulphydryl concentrations in maternal plasma (r 0.43, P=0.007) and between urate concentrations in maternal and cord plasma (r 0.37, P=0.026). CONCLUSION: Urate, bilirubin and sulphydryls are present in significantly higher concentrations in cord blood than in maternal blood. The increased levels of these antioxidants in cord plasma may contribute to the increased resistance of cord plasma to Cu2+-induced lipid peroxidation.     

PLGF、Bcl-2及FasL在胎儿生长受限中的研究

目的:探讨胎儿生长受限(fetal growth retriction,FGR)患儿母血及脐血中胎盘生长因子(placenta growth fac-tor,PLGF)浓度与胎盘组织中凋亡相关蛋白Bcl-2、FasL表达的关系。方法:采用双抗体夹心酶联免疫吸附法(ELISA)测定FGR组40例和同期足月正常体重儿(对照组)30例母血、脐血中PLGF浓度;免疫组化SP法检测胎盘组织中Bcl-2,FasL蛋白的表达。结果:①FGR组母血、脐血PLGF浓度与对照组比较,明显降低(P0.05);②Bcl-2在FGR组胎盘组织的表达比对照组降低,两组相比差异有统计学意义(P0.05);③FasL在FGR组胎盘组织的表达比对照组降低,两组相比差异有统计学意义(P0.05);④FGR组母血、脐血中PLGF浓度与胎盘组织中Bcl-2、FasL表达水平呈正相关。结论:母血、脐血PLGF减少可能是引起FGR的原因之一。胎盘组织中Bcl-2表达下降,FasL减弱可能是FGR发病的重要因素之一。在FGR中PLGF可通过上调Bcl-2和FasL的表达,抑制胎盘细胞凋亡,促进胎儿的发育。     

Polybrominated diphenyl ethers in maternal and fetal blood samples

Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in consumer goods, such as plastics, electronics, textiles, and construction material. PBDEs have been found in human milk, fat, and blood samples. Rodent studies indicate that PBDEs may be detrimental to neurodevelopment, possibly by lowering thyroid hormone concentrations in blood. In the present study, we determined concentrations of PBDEs and thyroid hormones in human fetal and maternal serum. Patients presenting in labor to Indiana University and Wishard Memorial County hospitals in Indianapolis, who were older than 18 years, were recruited to participate. Twelve paired samples of maternal and cord blood were obtained and analyzed using gas chromatographic mass spectrometry; thyroid hormone concentrations were determined by radioimmunoassay. Six congeners of PBDE were measured in maternal and fetal serum samples. The concentrations of total PBDEs found in maternal sera ranged from 15 to 580 ng/g lipid, and the concentrations found in fetal samples ranged from 14 to 460 ng/g lipid. Individual fetal blood concentrations did not differ from the corresponding maternal concentrations, indicating that measurement of maternal PBDE blood levels is useful in predicting fetal exposure; similarly, other reports have shown a high correlation between PBDE in mother's milk and fetal exposure. In accord with reports on other biologic samples, the tetrabrominated PBDE congener BDE-47 accounted for 53-64% of total PBDEs in the serum. The concentrations of PBDEs found in maternal and fetal serum samples were 20-106-fold higher than the levels reported previously in a similar population of Swedish mothers and infants. In this small sample, there was no apparent correlation between serum PBDEs and thyroid hormone concentrations. Our study shows that human fetuses in the United States may be exposed to relatively high levels of PBDEs. Further investigation is required to determine if these levels are specific to central Indiana and to assess the toxic potential of these exposure levels.     

Correlations between mercury concentrations in umbilical cord tissue and other biomarkers of fetal exposure to methylmercury in the Japanese population

Methylmercury (MeHg) is one of the most risky substances to affect humans through fish consumption, and the fetus is known to be in the most susceptible group. Our objective in this study is to examine the relationships of total mercury (THg) and MeHg concentrations between umbilical cord tissue and other tissues as biomarkers of fetal exposure to MeHg in the Japanese population. In total, 116 paired samples were collected in three Japanese districts, the Tsushima Islands, Fukuoka City, and Katsushika ward of metropolitan Tokyo. THg was measured for hair and THg and MeHg were measured in cord tissues, maternal blood, and cord blood. The relationships among tissues in Hg concentrations were similar among districts. Therefore, we analyzed the relationships using all the samples. More than 90% of Hg in cord tissue, cord blood, and maternal blood was MeHg. THg and MeHg in cord blood was about two times higher than in maternal blood. A strong correlation was found between THg and MeHg in cord tissue. The cord tissue THg and MeHg showed a strong correlation with cord blood Hg, which is recognized as the best biomarker for fetal exposure to MeHg. The findings of this study indicate the significance of cord tissue THg and MeHg as biomarkers for fetal exposure to MeHg at parturition.     

Dissolved Organochlorine and PAH Pollution Profiles in Lithuanian and Swedish Surface Waters

In recent decades, knowledge and concern regarding persistent organic pollutants and the environmental hazards they may pose have increased considerably, leading to international agreements such as the United Nations environment program Stockholm convention on persistent organic pollutants (POPs), to minimize further release of POPs into the environment (UNECE Protocol, 1979; UNEP Stockholm convention, 2001; UNECE Convention, 1998). National POP monitoring programs should be designed to identify, characterize and address the release of the POPs listed in the Stockholm convention. However, analyses of grab samples only provide crude snapshots of total concentrations at single points in space and time, which may be highly unrepresentative of average concentrations, and fail to account for differences in the POPs’ bioavailability and various other relevant factors. To obtain a better understanding of the fate and availability of pollutants in the environment it is necessary to obtain data regarding their site-specific and regional exposure levels. Exposure levels expressed in terms of total chemical concentrations do not reflect the actual exposure of organisms, and thus may not accurately reflect the true risks posed. Therefore, environmental monitoring programs would be improved by using reliable, integrative sampling methods that would not only allow time-weighted average concentrations of pollutants in the environment to be determined, but also facilitate assessments of the risks these chemicals pose to the environment.     

Polybrominated diphenyl ethers in paired samples of maternal and umbilical cord blood plasma and associations with house dust in a Danish cohort

Brominated flame retardants (BFRs), in particular the polybrominated diphenyl ethers (PBDEs), have been used in consumer products for many years to increase fire resistance. Recently, developmental neurotoxicity at very low levels has increased the concern about these compounds. The major objectives of this study were to investigate the maternal and fetal exposure to PBDEs on the basis of maternal and umbilical cord plasma samples and to study the extent of placental transfer for different PBDE congeners. The findings were also compared with previously observed PBDE levels and patterns determined in placental tissue from the same individuals, and the relationship with the external exposure from house dust from the participants’ homes was explored. Samples of maternal and umbilical cord plasma from a cohort of 51 pregnant women from the Copenhagen area were collected. Paired maternal and umbilical cord plasma were analysed for BDE-28, 37, 47, 85, 99, 100, 119, 138, 153, 154, 183, 209 and the brominated biphenyl BB-153 using automated SPE extraction and GC-HRMS for the tri- to hepta-BDEs and GC-LRMS (ECNI) for BDE-209. PBDEs were detected in all maternal and umbilical cord plasma samples. The sum of tri- to hexa-BDEs (ΣPBDE) in maternal plasma varied between 640 and 51,946 pg/g lipid weight (lw) with a median level of 1765 pg/g lw. In the umbilical cord samples ΣPBDE varied between 213 and 54,346 pg/g lw with a median of 958 pg/g lw. The levels observed in fetal and maternal plasma were highly correlated, but the placental transport of PBDE congeners was found to decrease with increasing diphenyl ether bromination. Maternal concentrations were significantly correlated (p < 0.05) for most congeners with the previously determined concentrations in placental tissue from the same individuals. Furthermore, positive correlations (p < 0.05) were found for BDE-28, 47, 100, 209 and ΣPBDE in maternal plasma and house dust as well as for ΣPBDE in umbilical cord plasma and house dust. The positive correlations for PBDEs for both maternal and umbilical cord plasma with house dust showed that domestic house dust is a significant source of human exposure to PBDEs in Denmark including in utero exposure.     

Inorganic mercury and methylmercury in placentas of Swedish women

We determined levels of inorganic mercury (I-Hg) and methylmercury in placentas from 119 Swedish women, not selected with respect to high exposure of mercury. Our objective was to relate placental Hg species with maternal and fetal blood concentrations and to evaluate possible associations with selenium. We performed the analyses using automated alkaline solubilization/reduction and cold-vapor atomic fluorescence spectrophotometry. I-Hg levels in placenta increased with an increasing number of maternal dental amalgam fillings (p < 0.001). Despite placental accumulation (median, 1.3 microg/kg; range, 0.18-6.7 microg/kg wet weight), a substantial fraction of maternal blood I-Hg, probably as Hg(0), reached the fetus. Although MeHg transferred easily to the fetus, it also accumulated in the placenta. On average, 60% of placental Hg was in the form of MeHg. The median concentration was 1.8 microg/kg (range, 0-6.2 microg/kg wet weight), more than twice the maternal blood concentration. We found significant associations between MeHg and selenium in both maternal and umbilical cord blood but not in the placenta. The associations were particularly obvious in freshwater fish consumers, probably reflecting that fish is a source of both MeHg and selenium. We found no correlations between I-Hg and selenium. This study increases the understanding of Hg, in its different forms, in human placenta and how they are related to maternal and fetal exposure.     

Relationship between polycyclic aromatic hydrocarbon-DNA adducts, environmental tobacco smoke, and child development in the World Trade Center cohort

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs), including benzo[a]pyrene (BaP), are air pollutants released by the World Trade Center (WTC) fires and urban combustion sources. BaP-DNA adducts provide a measure of PAH-specific genetic damage, which has been associated with increased risk of adverse birth outcomes and cancer. We previously reported that levels of BaP-DNA adducts in maternal and umbilical cord blood obtained at delivery were elevated among subjects who had resided within 1 mile of the WTC site during the month after 9/11; and that elevated blood adducts in combination with in utero exposure to environmental tobacco smoke (ETS) were significantly associated with decreased fetal growth. OBJECTIVE: Our aim was to assess possible effects of prenatal exposure to WTC pollutants on child development. METHODS: After 11 September 2001, we enrolled a cohort of nonsmoking pregnant women who delivered at three lower Manhattan hospitals. We have followed a subset of children through their third birthdays and measured cognitive and motor development using the Bayley-II Scales of Child Development (BSID-II). RESULTS: In multivariate analyses, we found a significant interaction between cord blood adducts and in utero exposure to ETS on mental development index score at 3 years of age (p = 0.02, n = 98) whereas neither adducts nor ETS alone was a significant predictor of (BSID-II) cognitive development. CONCLUSION: Although limited by small numbers, these results suggest that exposure to elevated levels of PAHs in conjunction with prenatal ETS exposure may have contributed to a modest reduction in cognitive development among cohort children.     

Persistent organic pollutant concentrations in first birth mothers across Mexico

This project was initiated by the North America Commission for Environmental Cooperation (CEC). Its main purpose was to obtain an initial profile on pregnant woman's exposure to persistent organic pollutants (POPs) in North America (Canada, the United States and Mexico). Persistent organic pollutants are transferred to the fetus via the placenta during the pregnancy or to the infant via maternal milk; therefore, the pregnant woman's body burden is important because of the higher exposures and potential health effects in the fetus and infant. This paper presents the results from 240 pregnant women in 10 Mexican cities, and includes the concentrations of various POPs such as polychlorinated biphenyls (PCBs), organochlorine pesticides and polychlorinated dibenzo dioxins and furans (PCDDs and PCDFs) in maternal plasma. We found concentrations of p,p'-DDE in maternal samples from Coatzacoalcos to be ～60% higher than those found in Ciudad Obregon, which had the second highest concentration. Pregnant women from Merida had higher mean concentrations of PCBs than all women in other regions. Results for PCDDs and PCDFs plus dioxin-like PCBs data were only available on the basis of composite samples, and their concentrations are similar in most cities except for Coatzacoalcos, which had more than double the concentration found in other cities. Although this study provides useful information on the variability of POPs in specific populations and possible regional/local differences, these results cannot be generalized to the entire Mexican population because of differences in age, gender, sources of exposure and nonrandom nature of the sample.     

Human exposure to heavy metals in the vicinity of Portuguese solid waste incinerators--Part 2: biomonitoring of lead in maternal and umbilical cord blood

As part of environmental health surveillance programs related to solid waste incinerators located near Lisbon and on Madeira Island, human biomonitoring projects have been implemented in Portugal, some of them focused on cross-sectional surveys of heavy metals in blood. One of the general aims of these programs is to provide Portuguese data on the extent and pattern of human exposure to the pollutants potentially released in the stack gases from the incinerators, namely heavy metals. The present investigation reports information specifically on blood lead levels of newborn-mother pairs living in the vicinity of the incinerators under study, as well as of statistically similar participants living outside the exposed area. For Lisbon, lead levels determined at the baseline period (T0), as well as three subsequent evaluations of potential specific impacts of the incinerator (T1, T2 and T3) are described in order to investigate spatial and temporal trends of human exposure to lead. Available data for Madeira, namely lead levels in blood from the study population before the incinerator started operation, is also described. For Lisbon, analyses showed a statistically significant decrease of lead concentrations in maternal (p<0.001) and umbilical cord blood (p<0.001) during the whole monitoring period. Practically "overt" transplacental exposure to lead was observed only in the Lisbon biomonitoring project and for some cross-sectional surveys. Baseline levels for Madeira were the lowest found in all observations already performed in both programs (maternal and umbilical cord mean lead levels of 0.4 microg/dl and 0.3 microg/dl, respectively). No statistical associations have been found between lead levels in blood and age neither for global populations from Lisbon and Madeira nor for specific groups included in the different observational periods.     

Heavy metals (lead, cadmium and mercury) in maternal, cord blood and placenta of healthy women

Lead, cadmium and mercury were measured in placental tissue, umbilical cord and maternal blood samples of 1578 women who delivered at the Al-Kharj King Khalid Hospital between 2005 and 2006. The aim of this study was to evaluate the status of heavy metal exposure in mothers and their newborns and to identify predictors of maternal exposure. Lead was detected in all cord and maternal blood and in 96% of placental tissues. Only in 0.89% and 0.83% of cord and maternal blood samples were the levels of lead above the CDC threshold limit of 10 μg/dl. Maternal blood lead was also higher (2.3%) than the German Reference value in women of 7 μg/dl. Approximately 9.3% of women had a placental lead above the 95th percentile in the range of 0.83-78 μg/g dry wt., a level of possible developmental toxicity. Cadmium was detected in 94.8% and 97.9% of cord and maternal blood samples respectively, though only five newborns had a cadmium level above the OSHA threshold limit of 5 μg/l. Comparing our results to the newly revised German Reference value for nonsmokers, 48.6% of mothers had blood cadmium levels >1.0 μg/l. We found as well that 25% of women had placental cadmium in the >75th percentile, in the range of 0.048-4.36 μg/g dry wt., which is likely to affect fetal growth and development. Of the maternal and cord blood samples, 11.2% and 13%, respectively, had mercury levels >5.8 μg/l, which is the EPA reference dose. Nearly 49% of women had mercury levels >2.0 μg/l, the German Reference value for those who consume fish ≤3 times a month. Around 50% of the mothers had placental mercury in the range of 0.031-13.0 μg/g dry wt. Regression analyses indicated that the levels of metals in the blood and placenta were influenced by several factors. This study provides informative baseline biomonitoring data and reveals a substantial exposure to heavy metals in non-occupationally exposed Saudi mothers and their newborns that might jeopardize the health of both. Additional research is also urgently needed to explore factors such as environment, diet, lifestyle and/or cultural habits contributing to maternal and fetal exposures. Preventive measures to eliminate or minimize the unnecessary risk of fetus exposure to heavy metals or other pollutants during pregnancy should be initiated once these factors are identified.     

胎儿宫内多环芳烃暴露水平及其母婴暴露关系研究

目的了解胎儿宫内多环芳烃(PAHs)暴露水平,并探讨母婴暴露关系。方法于2006年10月至2008年1月在太原市两所二级甲等医院中随机调查符合条件的347名孕产妇,进行流行病学调查和生物样品的收集,其中母婴匹配的有271对用于本次分析。采用改进的高效液相色谱法测定母亲外周静脉血及新生儿脐带血中7种PAHs水平。结果可供检测的271对血清样本中,芘及苯并(a)蒽的检出率分别为母90.94%和脐79.34%;母95.97%和脐85.03%,其余4种致癌性PAHs的检出率均在50%～70%左右。脐带血苯并(k)荧蒽(P=0.002)、苯并(a)芘(P=0.002)、二苯并(a,h)蒽(P<0.001)水平均高于母血清,差异有统计学意义。此外,新生儿血清中苯并(b)荧蒽浓度要稍高于母亲,但差异没有统计学意义(P=0.075)。结论新生儿脐带血中可检出多种致癌性多环芳烃,并且脐带血中PAHs水平与母体相当甚至高于母体水平。     

Concentrations of tocopherols and carotenoids in maternal and cord blood plasma.

OBJECTIVES: To determine the levels of tocopherols, retinol and carotenoids in maternal and umbilical cord blood plasma and to investigate the relationships between them. DESIGN: Venous blood plasma concentrations of alpha, gamma and delta-tocopherol, retinol, lutein, lycopene, zeaxanthin, beta-cryptoxanthin, alpha and beta-carotene were determined by HPLC in healthy pregnant women and in pair-matched umbilical cords. Plasma levels of triglycerides and cholesterol were also measured. SUBJECTS: Sixty-six women, between 10 and 20 weeks gestation, were recruited randomly during their first antenatal appointment. From this group, 40 pair-matched umbilical cord blood samples were obtained. RESULTS: Tocopherols, retinol, carotenoids and lipids were present in significantly higher (P < 0.001) concentrations in maternal plasma than in cord plasma. There was a significant correlation (r = 0.45, P < 0.005) between maternal and cord levels of gamma-tocopherol, but not of alpha-tocopherol, retinol or carotenoids. Tocopherols and carotenoids were significantly correlated with each other (P < 0.05) in maternal and cord plasma. CONCLUSIONS: Plasma levels of tocopherols, carotenoids and lipids are substantially lower at birth than in adulthood. There is a clear relationship between gamma-tocopherol levels in maternal and cord plasma. The importance of gamma-tocopherol in human nutrition should be further investigated. There are no significant relationships between plasma alpha-tocopherol and carotenoids in pregnant mothers and cords. More research is needed to elucidate the maternal-foetal transfer of tocopherols and carotenoids, and to examine the impact of maternal antioxidant nutrient status on neonatal antioxidant capacity. It is important to determine if a low level of tocopherols and carotenoids at birth is a normal stage of human development or indicative of deficiency.     

Relationships among polycyclic aromatic hydrocarbon-DNA adducts, proximity to the World Trade Center, and effects on fetal growth

Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by the World Trade Center (WTC) fires and various urban combustion sources. Benzo[a]pyrene (BaP) is a representative member of the class of PAHs. PAH-DNA adducts, or BaP-DNA adducts as their proxy, provide a measure of chemical-specific genetic damage that has been associated with increased risk of adverse birth outcomes and cancer. To learn whether PAHs from the WTC disaster increased levels of genetic damage in pregnant women and their newborns, we analyzed BaP-DNA adducts in maternal (n = 170) and umbilical cord blood (n = 203) obtained at delivery from nonsmoking women who were pregnant on 11 September 2001 and were enrolled at delivery at three downtown Manhattan hospitals. The mean adduct levels in cord and maternal blood were highest among newborns and mothers who resided within 1 mi of the WTC site during the month after 11 September, intermediate among those who worked but did not live within this area, and lowest in those who neither worked nor lived within 1 mi (reference group). Among newborns of mothers living within 1 mi of the WTC site during this period, levels of cord blood adducts were inversely correlated with linear distance from the WTC site (p = 0.02). To learn whether PAHs from the WTC disaster may have affected birth outcomes, we analyzed the relationship between these outcomes and DNA adducts in umbilical cord blood, excluding preterm births to reduce variability. There were no independent fetal growth effects of either PAH-DNA adducts or environmental tobacco smoke (ETS), but adducts in combination with in utero exposure to ETS were associated with decreased fetal growth. Specifically, a doubling of adducts among ETS-exposed subjects corresponded to an estimated average 276-g (8%) reduction in birth weight (p = 0.03) and a 1.3-cm (3%) reduction in head circumference (p = 0.04). The findings suggest that exposure to elevated levels of PAHs, indicated by PAH-DNA adducts in cord blood, may have contributed to reduced fetal growth in women exposed to the WTC event.