Pregnancy urinary concentrations of bisphenol A, parabens and other phenols in relation to serum levels of lipid biomarkers: Results from the EARTH study

The epidemiologic literature on associations between urinary phenol concentrations and lipid profiles during pregnancy is limited. We examined whether urinary concentrations of phenol and phenol replacement biomarkers were associated with serum lipid levels among pregnant women. This cross-sectional study included 175 women attending the Massachusetts General Hospital Fertility Center who enrolled in the Environment and Reproductive Health (EARTH) Study between 2005 and 2017 and had data available on urinary phenol biomarkers and serum lipids during pregnancy. We used linear regression models to assess the relationship between groups of urinary phenol and phenol replacement biomarkers and serum lipid levels [total cholesterol, high density lipoprotein (HDL), non-HDL, low-density lipoprotein (LDL) cholesterol, and triglycerides], while adjusting for age at sample collection, pre-pregnancy BMI, education, race, infertility diagnosis, cycle type, number of fetuses, trimester and specific gravity. In adjusted models, pregnant women with urinary propylparaben concentrations in the highest tertile had 10% [22 (95% CI = 5, 40) mg/dL], 12% [19 (95% CI = 2, 36) mg/dL] and 16% [19 (95% CI = 3, 35) mg/dL] higher mean total, non-HDL and LDL cholesterol, respectively, compared to women with concentrations in the lowest tertile. Similar elevations were observed for urinary bisphenol A concentrations. Urinary bisphenol S, benzophenone-3, triclosan, methylparaben, ethylparaben, and butylparaben were unrelated to serum lipids. Among pregnant women, urinary concentrations of bisphenol A and propylparaben were associated with higher serum levels of total, non-HDL and LDL cholesterol.

Peptide profiling in cow urine reveals molecular signature of physiology-driven pathways and in-silico predicted bioactive properties

Peptidomics allows the identification of peptides that are derived from proteins. Urinary peptidomics has revolutionized the field of diagnostics as the samples represent complete systemic changes happening in the body. Moreover, it can be collected in a non-invasive manner. We profiled the peptides in urine collected from different physiological states (heifer, pregnancy, and lactation) of Sahiwal cows. Endogenous peptides were extracted from 30 individual cows belonging to three groups, each group comprising of ten animals (biological replicates n = 10). Nano Liquid chromatography Mass spectrometry (nLC-MS/MS) experiments revealed 5239, 4774, and 5466 peptides in the heifer, pregnant and lactating animals respectively. Urinary peptides of <10 kDa size were considered for the study. Peptides were extracted by 10 kDa MWCO filter. Sequences were identified by scanning the MS spectra ranging from 200 to 2200 m/z. The peptides exhibited diversity in sequences across different physiological states and in-silico experiments were conducted to classify the bioactive peptides into anti-microbial, anti-inflammatory, anti-hypertensive, and anti-cancerous groups. We have validated the antimicrobial effect of urinary peptides on Staphylococcus aureus and Escherichia coli under an in-vitro experimental set up. The origin of these peptides was traced back to certain proteases viz. MMPs, KLKs, CASPs, ADAMs etc. which were found responsible for the physiology-specific peptide signature of urine. Proteins involved in extracellular matrix structural constituent (GO:0005201) were found significant during pregnancy and lactation in which tissue remodeling is extensive. Collagen trimers were prominent molecules under cellular component category during lactation. Homophilic cell adhesion was found to be an important biological process involved in embryo attachment during pregnancy. The in-silico study also highlighted the enrichment of progenitor proteins on specific chromosomes and their relative expression in context to specific physiology. The urinary peptides, precursor proteins, and proteases identified in the study offers a base line information in healthy cows which can be utilized in biomarker discovery research for several pathophysiological studies.

Multiomics Characterization of Preterm Birth in Low- and Middle-Income Countries

IMPORTANCE

Worldwide, preterm birth (PTB) is the single largest cause of deaths in the perinatal and neonatal period and is associated with increased morbidity in young children. The cause of PTB is multifactorial, and the development of generalizable biological models may enable early detection and guide therapeutic studies.

OBJECTIVE

To investigate the ability of transcriptomics and proteomics profiling of plasma and metabolomics analysis of urine to identify early biological measurements associated with PTB.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic/prognostic study analyzed plasma and urine samples collected from May 2014 to June 2017 from pregnant women in 5 biorepository cohorts in low- and middle-income countries (LMICs; ie, Matlab, Bangladesh; Lusaka, Zambia; Sylhet, Bangladesh; Karachi, Pakistan; and Pemba, Tanzania). These cohorts were established to study maternal and fetal outcomes and were supported by the Alliance for Maternal and Newborn Health Improvement and the Global Alliance to Prevent Prematurity and Stillbirth biorepositories. Data were analyzed from December 2018 to July 2019.

EXPOSURES

Blood and urine specimens that were collected early during pregnancy (median sampling time of 13.6 weeks of gestation, according to ultrasonography) were processed, stored, and shipped to the laboratories under uniform protocols. Plasma samples were assayed for targeted measurement of proteins and untargeted cell-free ribonucleic acid profiling; urine samples were assayed for metabolites.

MAIN OUTCOMES AND MEASURES

The PTB phenotype was defined as the delivery of a live infant before completing 37 weeks of gestation.

RESULTS

Of the 81 pregnant women included in this study, 39 had PTBs (48.1%) and 42 had term pregnancies (51.9%) (mean [SD] age of 24.8 [5.3] years). Univariate analysis demonstrated functional biological differences across the 5 cohorts. A cohort-adjusted machine learning algorithm was applied to each biological data set, and then a higher-level machine learning modeling combined the results into a final integrative model. The integrated model was more accurate, with an area under the receiver operating characteristic curve (AUROC) of 0.83 (95% CI, 0.72-0.91) compared with the models derived for each independent biological modality (transcriptomics AUROC, 0.73 [95% CI, 0.61-0.83]; metabolomics AUROC, 0.59 [95% CI, 0.47-0.72]; and proteomics AUROC, 0.75 [95% CI, 0.64-0.85]). Primary features associated with PTB included an inflammatory module as well as a metabolomic module measured in urine associated with the glutamine and glutamate metabolism and valine, leucine, and isoleucine biosynthesis pathways.

CONCLUSIONS AND RELEVANCE

This study found that, in LMICs and high PTB settings, major biological adaptations during term pregnancy follow a generalizable model and the predictive accuracy for PTB was augmented by combining various omics data sets, suggesting that PTB is a condition that manifests within multiple biological systems. These data sets, with machine learning partnerships, may be a key step in developing valuable predictive tests and intervention candidates for preventing PTB.

Predictors and reproducibility of urinary organophosphate ester metabolite concentrations during pregnancy and associations with birth outcomes in an urban population

BACKGROUND

Organophosphate esters (OPEs) are synthetic chemicals used as flame retardants and plasticizers in a variety of goods. Despite ubiquitous human exposures and laboratory evidence that prenatal OPE exposures may disrupt offspring metabolism, perinatal studies of OPE health effects are limited. The objectives of this study were to: 1) Determine predictors and reproducibility of urinary OPE biomarker concentrations during pregnancy, and 2) Estimate the relation of prenatal OPE exposures with birth outcomes and cord blood adipokine and insulin concentrations.

METHODS

We analyzed five OPE metabolites in urine samples collected at up to three visits during pregnancy from 90 women enrolled in the ORigins of Child Health And Resilience in Development (ORCHARD) pregnancy cohort in Baltimore, MD from 2017 to 2019. To quantify the variability of metabolite concentrations during pregnancy, we calculated intraclass correlation coefficients (ICCs) for each metabolite using mixed effects regression models. Using self-reported questionnaire data collected during gestation, we assessed possible sociodemographic and environmental/behavioral predictors of each OPE metabolite using generalized estimating equations to account for repeated exposure measures. We ascertained birth outcomes of 76 offspring from medical records, including weight-for-gestational age, length, ponderal index, and gestational age. In a subset of 37 infants, we measured cord blood concentrations of leptin, adiponectin, and insulin. To account for repeated exposure measures, we used linear structural equation models to assess the relations of standard deviation (SD) increases in prenatal OPE metabolite factor scores with continuous birth outcomes and cord blood biomarker concentrations.

RESULTS

ICCs ranged from 0.09 for isopropylphenyl-phenyl phosphate (ip-PPP) to 0.59 for bis(1,3-dichloro-2-propyl) phosphate (BDCIPP). We observed little consistency in environmental or behavioral predictors of OPE exposures, although concentrations were generally lower for samples collected in the afternoon compared to morning and winter compared to other seasons. In adjusted analyses, a SD increase in BDCIPP concentration was associated with a 0.06 g/cm3 (95% CI: 0.00, 0.12) greater ponderal index. A SD increase in BDCIPP was associated with a 0.37 (95% CI: - 0.62, - 0.13) SD lower insulin concentration and 0.24 (95% CI: - 0.39, - 0.08) SD lower leptin concentration. Other OPEs were not associated with infant outcomes.

CONCLUSIONS

These findings suggest some OPEs may be metabolic disruptors warranting investigation in larger studies.

Determination of Reference Intervals of Ratios of Concentrations of Urinary Iodine to Creatinine and Thyroid Hormone Concentrations in Pregnant Women Consuming Adequate Iodine in Harbin, Heilongjiang Province

The objectives of this study were to explore reference intervals of ratios of concentrations of urinary iodine to creatinine (UIC/UCr) in pregnant women, to determine specific reference intervals for thyroid hormone concentrations (FT₃, FT₄, TSH) in the first trimester of pregnancy, and provide a comprehensive evaluation of iodine nutritional status and thyroid function. Cross-sectional data analysis, including questionnaires and thyroid ultrasonograms, were used to exclude subjects who had a history of thyroid disease, a family history of thyroid disease, or thyroid morphological abnormalities. Tests of thyroid hormone were evaluated together with urinary iodine concentration (UIC), urinary creatinine concentration (UCr), and salt iodine concentration in pregnant women. For the sample of pregnant women eligible for inclusion, the 95% reference intervals of the bilateral limits of UIC/UCr and thyroid hormone concentrations in pregnant women were determined by the percentile method. Pregnant women were recruited in Harbin, Heilongjiang Province, a particular geographical area of China, where iodine nutrition is adequate. The median UIC was 141.47 μg/L, while the median UIC/UCr was 141.12 μg/g. The reference intervals of thyroid hormone concentrations in the first trimester were FT₃ 3.63-6.12 pmol/L, FT₄ 11.89-22.91 pmol/L, and TSH 0.013-3.814 mIU/L. The reference intervals of UIC/UCr were 52.47 to 532.09 μg/g (first trimester 47.25-353.91 μg/g, second trimester 57.95-639.08 μg/g, third trimester 46.98-494.73 μg/g).The established UIC/UCr medical reference intervals and thyroid hormone concentration reference intervals may be used for iodine nutritional assessment and thyroid disease screening in pregnant women.

Manganese is associated with increased plasma interleukin-1β during pregnancy, within a mixtures analysis framework of urinary trace metals

Exposure to trace metals may impact reproductive health outcomes through perturbations in maternal immune signaling molecules. We conducted a cross-sectional study of 390 pregnant women from the LIFECODES birth cohort and investigated the associations between 17 urinary metals and five immune biomarkers measured in the 3rd trimester (median 26 weeks gestation). We used linear regression to estimate pair-wise associations and applied elastic net and Bayesian kernel machine regression to identify important contributing exposures analytes as well as non-linear effects. Maternal urinary manganese, nickel, and barium were positively associated with maternal plasma interleukin-1β (IL-1β). Elastic net and Bayesian kernel machine regression identified manganese as the dominant trace metal in association with IL-1β. An interquartile range difference in manganese (0.6 μg/L) was associated with a 29 % increase in IL-1β (95 % CI: 12.4-48.2). In conclusion, trace metal exposures were associated with biomarkers of immune perturbations, and this warrants further investigation.

Environmental phthalate exposure and preterm birth in the PROTECT birth cohort

BACKGROUND

Preterm birth is a global public health issue and rates in Puerto Rico are consistently among the highest in the USA. Exposures to environmental contaminants might be a contributing factor.

METHODS

In a preliminary analysis from the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) cohort (n = 1090), we investigated the association between urinary phthalate metabolite concentrations measured at three study visits (targeted at 20, 24, and 28 weeks of gestation) individually and averaged over pregnancy with gestational age at delivery and preterm birth. We additionally assessed differences in associations by study visit and among preterm births with a spontaneous delivery.

RESULTS

Compared to women in the general USA population, urinary concentrations of metabolites of di-n-butyl phthalate (DBP) and di-isobutyl phthalate (DiBP) were higher among pregnant women in Puerto Rico. Interquartile range (IQR) increases in pregnancy-averages of urinary metabolites of DBP and DiBP were associated with shorter duration of gestation and increased odds of preterm birth. An IQR increase in mono-n-butyl phthalate (MBP), a metabolite of DBP, was associated with 1.55 days shorter gestation (95% confidence interval [CI] = -2.68, -0.42) and an odds ratio (OR) of 1.42 (95% confidence interval [CI]: 1.07, 1.88) for preterm birth. An IQR increase in mono-isobutyl phthalate (MiBP), a metabolite of DiBP, was associated with 1.16 days shorter gestation (95% CI = -2.25, -0.08) and an OR of 1.32 (95% CI: 1.02, 1.71) for preterm birth. Associations were greatest in magnitude for urinary concentrations measured at the second study visit (median 23 weeks gestation). DiBP metabolite associations were greatest in magnitude in models of spontaneous preterm birth. No associations were detected with other phthalate metabolites, including those of di-2-ethylhexyl phthalate.

CONCLUSION

Among pregnant women in the PROTECT cohort, DBP and DiBP metabolites were associated with increased odds of preterm birth. These exposures may be contributing to elevated rates of preterm birth observed in Puerto Rico.

Serum iodine concentration in pregnant women and its association with urinary iodine concentration and thyroid function

OBJECTIVE

This study aims to evaluate the association of serum iodine concentration (SIC) with urinary iodine concentration (UIC) and thyroid function in pregnant women, as well as to provide the reference range of SIC of pregnant women in iodine-sufficiency area.

METHODS

Pregnant women were enrolled in the Department of Obstetrics, Tanggu Maternity Hospital, Tianjin from March 2016 to May 2017. Fasting venous blood and spot urine samples were collected. Serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyroglobulin (Tg), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), UIC and SIC were measured.

RESULTS

One thousand and ninety-nine participants were included in this study. The median UIC was 156 μg/L. The median SIC was 108 μg/L, and the 95% reference interval for SIC was 65.6-164.7 μg/L. SIC was positively correlated with UIC (r = 0.12, P < 0.001), FT3 (r = 0.23, P < 0.001), and FT4 (r = 0.50, P < 0.001) and was inversely correlated with TSH (r = -0.14, P < 0.001). Pregnant women with a SIC < 79.9 μg/L had a higher risk of hypothyroxinemia compared to those with higher SIC (OR = 2.44, 95% CI: 1.31-4.75). Those having SIC > 138.5 μg/L were more likely to have thyrotoxicosis than those with lower SIC values (OR = 13.52, 95% CI: 4.21-43.36).

CONCLUSIONS

Serum iodine level is associated with UIC and thyroid function in pregnant women. Low SIC was associated with increased risk for iodine deficiency and hypothyroxinemia, while high SIC was related to excess and thyrotoxicosis.

A repeated measures study of phenol, paraben and Triclocarban urinary biomarkers and circulating maternal hormones during gestation in the Puerto Rico PROTECT cohort

INTRODUCTION

Prenatal exposure to some phenols and parabens has been associated with adverse birth outcomes. Hormones may play an intermediate role between phenols and adverse outcomes. We examined the associations of phenol and paraben exposures with maternal reproductive and thyroid hormones in 602 pregnant women in Puerto Rico. Urinary triclocarban, phenol and paraben biomarkers, and serum hormones (estriol, progesterone, testosterone, sex-hormone-binding globulin (SHBG), corticotropin-releasing hormone (CRH), total triiodothyronine (T3), total thyroxine (T4), free thyroxine (FT4) and thyroid-stimulating hormone (TSH)) were measured at two visits during pregnancy.

METHODS

Linear mixed models with a random intercept were constructed to examine the associations between hormones and urinary biomarkers. Results were additionally stratified by study visit. Results were transformed to hormone percent changes for an inter-quartile-range difference in exposure biomarker concentrations (%Δ).

RESULTS

Bisphenol-S was associated with a decrease in CRH [(%Δ -11.35; 95% CI: -18.71, - 3.33), and bisphenol-F was associated with an increase in FT4 (%Δ: 2.76; 95% CI: 0.29, 5.22). Butyl-, methyl- and propylparaben were associated with decreases in SHBG [(%Δ: -5.27; 95% CI: -9.4, - 1.14); (%Δ: -3.53; 95% CI: -7.37, 0.31); (%Δ: -3.74; 95% CI: -7.76, 0.27)]. Triclocarban was positively associated with T3 (%Δ: 4.08; 95% CI: 1.18, 6.98) and T3/T4 ratio (%Δ: 4.67; 95% CI: -1.37, 6.65), and suggestively negatively associated with TSH (%Δ: -10.12; 95% CI: -19.47, 0.32). There was evidence of susceptible windows of vulnerability for some associations. At 24-28 weeks gestation, there was a positive association between 2,4-dichlorophenol and CRH (%Δ: 9.66; 95% CI: 0.67, 19.45) and between triclosan and estriol (%Δ: 13.17; 95% CI: 2.34, 25.2); and a negative association between triclocarban and SHBG (%Δ: -9.71; 95% CI:-19.1, - 0.27) and between bisphenol A and testosterone (%Δ: -17.37; 95% CI: -26.7, - 6.87).

CONCLUSION

Phenols and parabens are associated with hormone levels during pregnancy. Further studies are required to substantiate these findings.

Exposure to prenatal secondhand smoke and early neurodevelopment: Mothers and Children's Environmental Health (MOCEH) study

BACKGROUND

The association between exposure to secondhand smoke (SHS) during pregnancy and a child's neurodevelopment has not been established yet. We explored the association between prenatal exposure to SHS and neurodevelopment at 24 months of age considering genetic polymorphism and breastfeeding in 720 mothers and their offspring enrolled in the Korean multicenter birth cohort study (Mothers and Children Environmental Health, MOCEH).

METHODS

We quantified urine cotinine concentrations in mothers once from 12th to 20th gestational weeks and excluded those whose urine cotinine levels exceeded 42.7 ng/ml to represent SHS exposure in early pregnancy. Mental developmental index (MDI) and psychomotor developmental index (PDI) values were measured using the Korean version of the Bayley Scales of Infant Development II (K-BSID-II) at 24 months of age. A general linear model was used to assess the relationship between maternal urinary cotinine level and neurodevelopment.

RESULTS

MDI scores were inversely associated with cotinine [β = - 2.73; 95% confidence interval (CI): - 5.32 to - 0.15] in children whose mothers had early pregnancy urinary cotinine levels >1.90 ng/ml. No association was evident in children whose mothers had cotinine levels ≤1.90 ng/ml. This negative association was more pronounced in children whose mothers had both Glutathione S-transferases mu 1 (GSTM1) and theta 1 (GSTT1) null type [β = - 5.78; 95% CI: -10.69 to - 0.87], but not in children whose mothers had any present type of GSTM1/GSTT1 [β = - 1.64; 95% CI: -4.79 to 1.52]. The association was no longer significant when children received breast milk exclusively for up to 6 months [β = - 0.24; 95% CI: -4.69 to 4.20] compared to others [β = - 3.75; 95% CI: -7.51 to 0.00]. No significant association was found for PDI.

CONCLUSIONS

Maternal exposure to SHS during pregnancy may result in delayed MDI in early childhood. This effect might be modified by genetic polymorphism and breastfeeding behavior.

Organophosphate Pesticide Metabolite Concentrations in Urine during Pregnancy and Offspring Nonverbal IQ at Age 6 Years

BACKGROUND

Susceptibility to organophosphate (OP) pesticide neurotoxicity may be greatest during the prenatal period; however, previous studies have produced mixed findings concerning in utero OP pesticide exposure and child cognition.

OBJECTIVES

Our objective was to determine whether maternal urinary concentrations of OP pesticide metabolites are inversely associated with child nonverbal IQ at 6 y of age and to examine potential effect measure modification by the PON1 gene.

METHODS

Data came from 708 mother–child pairs participating in the Generation R Study. Maternal urine concentrations of six dialkylphosphates (DAPs), collected at [Formula: see text], 18–25, and [Formula: see text] of gestation, were determined. Child nonverbal IQ was measured at 6 y of age using the Mosaics and Categories subtests from the Snijders-Oomen Nonverbal Intelligence Test-Revised. PON1 was determined in cord blood for 474 infants. Multiple linear regression models were fit to estimate the DAP-IQ associations and PON1 interactions.

RESULTS

Overall, associations between child nonverbal IQ and maternal DAP concentrations were small and imprecise, and these associations were inconsistent across urine sampling periods. Howover, for a 10-fold difference in total DAP concentration for the [Formula: see text] of gestation samples, adjusted child nonverbal IQ was 3.9 points lower (95% CI: [Formula: see text], [Formula: see text]). Heterogeneity in the DAP–IQ association by PON1 gene allele status was not observed ([Formula: see text]).

CONCLUSIONS

Consistent evidence of an association between higher maternal urinary DAP concentrations and lower child IQ scores at 6 y of age was not observed. There was some evidence for an inverse relation of child nonverbal IQ and late pregnancy urinary DAPs, but the estimated association was imprecise. https://doi.org/10.1289/EHP3024.

Maternal urinary 2-hydroxynaphthalene and birth outcomes in Taiyuan, China

BACKGROUND

Naphthalene is the simplest polycyclic aromatic hydrocarbon (PAH). It is easily emitted into the atmosphere, posing a significant risk to human health. However, limited studies have described the impact of naphthalene exposure on birth outcomes. In this study, we investigated the association between the maternal urinary metabolites of naphthalene, 2-hydroxynaphthalene (2-OH NAP), and birth outcomes.

METHOD

In the present study, four urinary PAH metabolites were measured in 263 pregnant women during late pregnancy. Multiple linear regression analysis was used to analyze the relationship between the concentrations of 2-OH NAP and birth outcomes, and restricted cubic spline models were further used to examine the shapes of the dose-response association.

RESULT

General linear models showed that prenatal urinary 2-OH NAP was associated with lower birth weight (BW) (- 4.38% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.049) and higher cephalization index (CI) (4.30% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.038). These associations were linear and significant when 2-OH NAP was modeled as a continuous variable in restricted cubic spline models (P _linear = 0.0293 for 2-OH NAP and BW; P _linear = 0.0326 for 2-OH NAP and CI). Multiple linear regression data indicated that each 1 ln-unit increase in 2-OH NAP was significantly associated with a 2.09 g/cm increase in the CI. The associations among 2-OH NAP, BW, and CI were also observed in a subset of participants residing close to arterial traffic.

CONCLUSION

Our data indicated that prenatal exposure to naphthalene had an adverse effect on fetal birth outcomes, especially the brain development index. Reduced exposure to naphthalene may improve newborn health outcomes. In Taiyuan, naphthalene may result from traffic pollution.

Unexpected, ubiquitous exposure of pregnant Brazilian women to diisopentyl phthalate, one of the most potent antiandrogenic phthalates

BACKGROUND

Human exposure to phthalates and other non-persistent chemicals in developing countries is largely unknown. A preliminary analysis of urinary samples from pregnant Brazilian women revealed the presence of metabolites of Diisopentyl phthalate (DiPeP).

OBJECTIVES

Reliably quantify DiPeP metabolites in human urine and investigate the potential antiandrogenic activity of this phthalate in rats.

METHODS

We initiated a pilot pregnancy cohort in Curitiba, Brazil, to examine phthalate exposure in urine samples collected in early pregnancy (n = 50) or pooled samples from early, mid and late pregnancy (n = 44). Our well established phthalate method was modified to include the primary DiPeP metabolite, monoisopentyl phthalate (MiPeP), and two additional secondary oxidized metabolites, 3OH-MiPeP and 4OH-MiPeP. In a parallel approach, we orally exposed pregnant rats to DiPeP or Di-n-butyl phthalate (DnBP; reference phthalate) at 0, 125, 250, and 500 mg/kg/day from gestation day 14 to 18 and measured ex vivo fetal testis testosterone production.

RESULTS

We were able to detect and quantify specific DiPeP metabolites in nearly all (98%) of the early pregnancy urine samples and in all gestational pool samples with a median concentration for MiPeP of 3.65 and 3.15 μg/L, respectively, and for the two oxidized metabolites between 1.00 and 1.70 μg/L. All three urinary DiPeP metabolites were strongly correlated (r = 0.89 to 0.99). In the rat model, the effective dose (mg/kg/day) inhibiting fetal testosterone production by 50% (ED₅₀ [95% confidence interval]) was 93.6 [62.9-139.3] for DiPeP which was significantly lower than for DnBP (220.3 [172.9-280.7]), highlighting the strong antiandrogenic potency of DiPeP within the spectrum of the phthalates.

CONCLUSIONS

We unveiled and confirmed the exposure of pregnant Brazilian women to DiPeP via specific urinary metabolites. This unexpected and ubiquitous DiPeP exposure indicates to unique DiPeP exposure sources in Brazil. These exposures spark considerable concern because DiPeP is one of the most potent antiandrogenic phthalates.

A Comparison of Iodine Status in Children and Pregnant Women After a Policy Change in the Iodized Salt Standard in Shanghai, China

In Shanghai, a new iodized salt standard was implemented in 2012. To provide evidence to the government, we compared iodine status before (35 mg/kg) and after (30 mg/kg) adjustment in vulnerable populations living in Shanghai. The probability-proportional-to-size sampling technique was used to select at least 360 pregnant women for urine iodine test and at least 1200 students for thyroid measurement and the household salt test. Of these students, at least 360 performed urine iodine test. The median thyroid volume and the median household salt iodine concentration of children aged 8-10 years were 1.80 ml and 24.8 mg/kg in 2015, and 0.97 ml and 28.3 mg/kg in 2011. The median urine iodine concentration (UIC) of pregnant women was 126.52 and 139.77 μg/L in 2015 and 2011. All differences were statistically significant (P < 0.05). The median UIC of students was 171.40 and 181.63 μg/L in 2015 and 2011, the difference was not statistically significant. Multivariate linear regression analysis showed that thyroid volume in children was associated with sex, age, region, and household salt iodized concentration. The current iodized salt concentration meets the basic needs of the population's iodine requirements except for pregnant women. Periodic monitoring is necessary particularly in vulnerable groups.

Community Water Fluoridation and Urinary Fluoride Concentrations in a National Sample of Pregnant Women in Canada

BACKGROUND

Fluoride exposures have not been established for pregnant women who live in regions with and without community water fluoridation.

OBJECTIVE

Our aim was to measure urinary fluoride levels during pregnancy. We also assessed the contribution of drinking-water and tea consumption habits to maternal urinary fluoride (MUF) concentrations and evaluated the impact of various dilution correction standards, including adjustment for urinary creatinine and specific gravity (SG).

METHODS

We measured MUF concentrations in spot samples collected in each trimester of pregnancy from 1,566 pregnant women in the Maternal-Infant Research on Environmental Chemicals cohort. We calculated intraclass correlation coefficients (ICCs) to assess variability in MUF concentrations across pregnancy. We used regression analyses to estimate associations between MUF levels, tea consumption, and water fluoride concentrations as measured by water treatment plants.

RESULTS

Creatinine-adjusted MUF values ([Formula: see text]; milligrams per liter) were almost two times higher for pregnant women living in fluoridated regions ([Formula: see text]) compared with nonfluoridated regions ([Formula: see text]; [Formula: see text]). MUF values tended to increase over the course of pregnancy using both unadjusted values and adjusted values. Reproducibility of the unadjusted and adjusted MUF values was modest ([Formula: see text]). The municipal water fluoride level was positively associated with creatinine-adjusted MUF ([Formula: see text], 95% CI: 0.46, 0.57), accounting for 24% of the variance after controlling for covariates. Higher MUF concentrations correlated with numbers of cups of black ([Formula: see text] but not green tea ([Formula: see text]). Urinary creatinine and SG correction methods were highly correlated ([Formula: see text]) and were interchangeable in models examining predictors of MUF.

CONCLUSION

Community water fluoridation is a major source of fluoride exposure for pregnant women living in Canada. Urinary dilution correction with creatinine and SG were shown to be interchangeable for our sample of pregnant women. https://doi.org/10.1289/EHP3546.

Urine and toenail cadmium levels in pregnant women: A reliability study

BACKGROUND

Cadmium, as measured in human tissue, has been associated with numerous health outcomes. However, few studies have evaluated the reliability of cadmium measurements across different biologic samples. We evaluated toenail cadmium levels over time and compared toenail cadmium to urinary cadmium. We also evaluated the relationship between biomarker concentrations and cigarette smoking, a known source of cadmium exposure.

METHODS

Cadmium was assessed in urine and toenail samples collected from 1338 pregnant women participating in the New Hampshire Birth Cohort Study. Each participant was asked to provide a urine and a toenail sample at enrollment (between 24 and 28 weeks gestation) and another toenail sample 2-8 weeks postpartum. Cadmium concentrations were determined using inductively-coupled plasma mass spectrometry. Spearman correlations were assessed for cadmium in the toenails across the two-time points and comparing toenail and urine levels. Smoking status was evaluated as a predictor of cadmium levels.

RESULTS

Toenail cadmium assessed during pregnancy and postpartum were modestly correlated (R = 0.3, p < 0.0001). However, urine and toenail cadmium levels were unrelated (R = -0.03, p = 0.46). Both toenail and urinary cadmium levels were associated with women's smoking status.

CONCLUSION

Our findings suggest that both toenail and urinary cadmium concentrations reflect the major source of exposure - cigarette smoking. Toenail cadmium concentrations are modestly reproducible pre- and postpartum; but do not appear to be related to urinary cadmium and thus likely represent different windows and chronicity of exposure among pregnant women.

Adjusting urinary chemical biomarkers for hydration status during pregnancy

One way of assessing a population's exposure to environmental chemicals is by measuring urinary biomarker concentrations, which can vary depending on the hydration status of the individual. The physiological changes that occur during pregnancy can impact the hydration adjustment approaches, such as calculating the individual's urinary flow rate (UFR), or adjusting concentrations using specific gravity (SG) or creatinine. A total of 1260 serial spot urine samples were collected from 80 women, averaging 32.4 years of age, throughout and shortly after pregnancy. The relationship between each approach was examined and time of day and across pregnancy differences were tested using linear mixed models. The correlation between the calculated excretion rate and each of the adjustment techniques was examined on a selection of seven phthalate metabolites. Based on the linear mixed model results, we found that UFR and creatinine excretion rates differed systematically across the population, with respect to body mass index (BMI) and time. SG differed with respect to BMI, but there were no systematic time trends. SG had the highest within-person reproducibility, according to the intraclass correlation coefficient (ICC). The excretion rate of each of the phthalates was most strongly correlated with the SG-standardized concentration. This analysis showed that SG showed a slightly better within-person reproducibility and the least amount of systematic variation when compared to creatinine adjustment. Therefore, SG correction appears to be a favorable approach for correcting for the hydration status of the pregnant women from this cohort.

Variability of urinary pesticide metabolite concentrations during pregnancy in the MARBLES Study

BACKGROUND

Variability of short-lived urinary pesticide metabolites during pregnancy raises challenges for exposure assessment.

OBJECTIVES

For urinary metabolite concentrations 3-phenoxybenzoic acid (3-PBA) and 3,5,6-trichloro-2-pyridinol (TCPy), we assessed: (1) temporal variability; (2) variation of two urine specimens within a trimester; (3) reliability for pesticide concentrations from a single urine specimen to classify participants into exposure tertiles; and (4) seasonal or year variations.

METHODS

Pregnant mothers (N = 166) in the MARBLES (Markers of Autism Risk in Babies-Learning Early Signs) Study provided urine specimens (n = 528). First morning void (FMV), pooled, and 24-h specimens were analyzed for 3-PBA and TCPy. For 9 mothers (n = 88 specimens), each urine specimen was analyzed separately (not pooled) to estimate within- and between-person variance components expressed as intraclass correlation coefficients (ICC). Pesticide concentrations from two specimens within a trimester were also assessed using ICC's. Agreement for exposure classifications was assessed with weighted Cohen's kappa statistics. Longitudinal mixed effect models were used to assess seasonal or year variations.

RESULTS

Urinary pesticide metabolites were detected in ≥ 93% of specimens analyzed. The highest ICC from repeated individual specimens was from specific gravity-corrected FMV specimens for 3-PBA (ICC=0.13). Despite high within-person variability, the median concentrations did not differ across trimesters. Concentrations from pooled specimens had substantial agreement predicting exposure categories for TCPy (K = 0.67, 95% CI (0.59, 0.76)) and moderate agreement for 3-PBA (K = 0.59, 95% CI (0.49, 0.69)). TCPy concentrations significantly decreased from 2007 to 2014.

CONCLUSIONS

Pooled specimens may improve exposure classification and reduce laboratory costs for compounds with short biological half-lives in epidemiological studies.

Associations of early life urinary triclosan concentrations with maternal, neonatal, and child thyroid hormone levels

BACKGROUND

Triclosan, an antimicrobial agent used in some consumer products, reduces endogenous thyroid hormone concentrations in rodents. Despite ubiquitous triclosan exposure and the importance of thyroid hormones for normal fetal development, few human studies have examined the impact of triclosan exposure on maternal, neonatal, or child thyroid hormones.

METHODS

In the HOME Study, a prospective cohort from Cincinnati, OH, we measured urinary triclosan concentrations up to three times in pregnant women between 16weeks and delivery, and up to three times in children between age 1-3years. We quantified serum concentrations of thyroid stimulating hormone and total and free thyroxine and triiodothyronine in mothers at 16-weeks gestation (n=202), neonates at delivery (n=274), and children at age 3years (n=153). We estimated covariate-adjusted differences in thyroid hormones with a 10-fold increase in triclosan using linear regression and multiple informants models.

RESULTS

Triclosan was not associated with thyroid hormones during pregnancy. We observed a few associations of triclosan concentrations with thyroid hormone concentrations in neonates at delivery and children at age 3years. Higher gestational triclosan, particularly around the time of delivery, was associated with lower cord serum total thyroxine (β: 0.3μg/dL; 95% CI: -0.6, -0.0). Childhood triclosan, particularly at age 1year, was positively associated with total thyroxine at age 3years (β: 0.7μg/dL; 95% CI: 0.3, 1.2).

CONCLUSION

Our findings suggest that triclosan exposure may influence some features of neonatal and early child thyroid function. Given the large number of comparisons we made, these findings should be replicated in other cohorts.

Environmental phenol associations with ultrasound and delivery measures of fetal growth

Environmental phenols are used commonly in personal care products and exposure is widespread in pregnant women. In this study, we sought to assess the association between maternal urinary phenol concentrations in pregnancy and fetal growth. The study population included 476 mothers who participated in the prospective LIFECODES birth cohort between 2006 and 2008 at Brigham and Women's Hospital in Boston, Massachusetts, USA. Dichlorophenols (DCPs), benzophenone-3, parabens, triclosan, triclocarban, and bisphenol-S were measured in urine from three time points during pregnancy and averaged. Outcome measures were all standardized to create gestational-age specific z-scores and included: 1) birth weight; 2) ultrasound parameters measured at up to two time points in pregnancy (head and abdominal circumference and femur length); and 3) ultrasound estimates of fetal weight from two time points in combination with birth weight. Models were stratified to investigate sex differences. Inverse associations were observed between average 2,4- and 2,5-DCP concentrations and birth weight z-scores in males. For example, an interquartile range difference in 2,4-DCP was associated with a 0.18 standard deviation decrease in birth weight z-score (95% confidence interval [CI]=-0.33, -0.02). These associations were observed in models that included repeated ultrasound estimates of fetal weight during gestation as well. Also in males, we noted inverse associations between average triclosan exposure over pregnancy and estimated fetal weight combined with birth weight in repeated measures models. For females, associations were generally null. However, mothers with a detectable concentration of bisphenol-S at any of the study visits had lower weight females. In conclusion, we observed inverse associations between indicators of maternal phenol exposure during pregnancy and fetal growth, with several differences observed by sex.

Early life bisphenol A exposure and neurobehavior at 8years of age: Identifying windows of heightened vulnerability

BACKGROUND

Early life BPA exposure could affect neurobehavior, but few studies have investigated whether there are developmental periods when the fetus or child is more vulnerable to these potential effects.

OBJECTIVES

We explored windows of vulnerability to BPA exposure in a multiethnic cohort of 228 mothers and their children from Cincinnati, Ohio.

METHODS

We measured urinary BPA concentrations at up to two prenatal and six postnatal time points from the 2nd trimester of pregnancy until the child was age 8years. At age 8years, we administered the Behavioral Assessment System for Children-2 (BASC-2), Behavior Rating Inventory of Executive Function, and Wechsler Intelligence Scale for Children-IV. We estimated covariate-adjusted differences in composite scores from each instrument using a multiple informant model designed to identify heightened windows of vulnerability.

RESULTS

Among all children, there was not strong evidence that the associations between BPA and neurobehavior varied by the timing of exposure (Visit x BPA p-values≥0.16). However, child sex modified the associations of repeated BPA measures with BASC-2 scores (Visit x Sex x BPA p-values=0.02-0.23). For example, each 10-fold increase in prenatal BPA was associated with more externalizing behaviors in girls (β=6.2, 95% CI: 0.8, 11.6), but not boys (β=-0.8, 95% CI: -5.0, 3.4). In contrast, a 10-fold increase in 8-year BPA was associated with more externalizing behaviors in boys (β=3.9, 95% CI: 0.6, 7.2), but not girls (β=0.3, 95% CI: -3.5, 4.1).

CONCLUSIONS

We found that sex-dependent associations between BPA and child neurobehavior may depend on the timing of BPA exposure.

Phthalates and thyroid function in preschool age children: Sex specific associations

BACKGROUND

Research relating either prenatal or concurrent measures of phthalate exposure to thyroid function in preschool children is inconclusive.

METHODS

In a study of inner-city mothers and their children, metabolites of di-n-butyl phthalate, butylbenzyl phthalate, di-isobutyl phthalate, di(2-ethylhexyl) phthalate, and diethyl phthalate were measured in a spot urine sample collected from women in late pregnancy and from their children at age 3years. We measured children's serum free thyroxine (FT4) and thyroid stimulating hormone (TSH) at age 3. Linear regression models were used to investigate the associations between phthalate metabolites, measured in maternal urine during late pregnancy and measured in child urine at age 3 and thyroid function measured at age 3.

RESULTS

Mean concentrations (ranges) were 1.42ng/dL (1.02-2.24) for FT4, and 2.62uIU/mL (0.61-11.67) for TSH. In the children at age 3, among girls, FT4 decreased with increasing log_e mono-n-butyl phthalate [estimated b=-0.06; 95% CI: (-0.09, -0.02)], log_e mono-isobutyl phthalate [b=-0.05; 95% CI: (-0.09, -0.01)], log_e monoethyl phthalate [b=-0.04; 95% CI: (-0.07, -0.01)], and log_e mono(2-ethyl-5-hydroxyhexyl) phthalate [b=-0.04; 95% CI: (-0.07, -0.003)] and log_e mono(2-ethyl-5-oxy-hexyl) phthalate [b=-0.04; 95% CI: (-0.07, -0.004)]. In contrast, among boys, we observed no associations between FT4 and child phthalate metabolites at age 3. On the other hand, in late gestation, FT4 increased with increasing log_e mono-(2-ethylhexyl) phthalate [estimated b=0.04; 95% CI: (0.02, 0.06)] and no sex difference was observed. We found no associations between phthalate biomarkers measured in either the child or prenatal samples and TSH at age 3.

CONCLUSIONS

The data show inverse and sex specific associations between specific phthalate metabolites measured in children at age 3 and thyroid function in preschool children. These results may provide evidence for the hypothesis that reductions in thyroid hormones mediate associations between early life phthalate exposure and child cognitive outcomes.

Thyroid hormone parameters during pregnancy in relation to urinary bisphenol A concentrations: A repeated measures study

BACKGROUND

Maternal supply of thyroid hormones during pregnancy serves a critical role in fetal development. Although animal and in vitro studies provide evidence for thyroid hormone disruption as a result of bisphenol A (BPA) exposure, there is still a lack of evidence in human studies, particularly in the context of pregnancy.

OBJECTIVES

We aimed to explore the associations between urinary BPA concentrations and plasma thyroid hormone parameters during gestation in pregnant women, and also investigated potential windows of vulnerability during gestation.

METHODS

Our study population included 116 cases of preterm birth and 323 controls from a nested case-control study. We measured BPA in urine and thyroid hormone parameters in plasma samples collected at up to four study visits during pregnancy (median for each visit: 9.64, 17.9, 26.0, and 35.1weeks gestation). We used linear mixed models for repeated measures analyses, and multivariate linear regression models stratified by study visit to explore potential windows of susceptibility.

RESULTS

In our repeated measures analysis, BPA and thyrotropin (TSH) were inversely associated. An interquartile range (IQR) increase in BPA was associated with an 8.21% decrease in TSH (95% confidence interval [CI]: -14.2, -1.83), and a 4.79% increase in free T4 (95% CI: 0.82, 8.92). BPA and TSH were also inversely associated in our cross-sectional analyses at visits 3 and 4.

CONCLUSIONS

Our results suggest that TSH is inversely associated with urinary BPA in a consistent manner across pregnancy. Disruption of TSH levels during pregnancy can potentially impact child development and interfere with normal birth outcomes.

Season-dependent concentrations of urinary phthalate metabolites among Chinese pregnant women: Repeated measures analysis

In utero exposure to phthalates may have adverse effects on pregnant women and their offsprings. Therefore, the exposure level of these substances among individuals, particularly among sensitive population, is of concern. The objective of the present study is to characterize urinary concentrations of phthalate metabolites at multiple time points during pregnancy in Chinese women. A total of 3455 pregnant women were included from Ma'anshan Birth Cohort in China. Spot urine samples in the morning (8:00-10:00) and questionnaires were obtained at three separate visits (approximately in 10, 26, and 34 gestational weeks). Seven phthalate metabolites from urine samples were analyzed, including monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), mono benzyl phthalate (MBzP), mono-2-ethylhexyl phthalate (MEHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP). Geometric means of concentrations were ranged from 0.05 to 41.0ng/mL for all the metabolites mentioned above. No individual exposure level was above the 95th percentiles for all the seven phthalates. On the three separate visits, 0.5%, 0.9% and 1.2% of the participants had coexposure to above the 75th percentiles for all metabolites. Taken these visits together, a total of 29 urine samples had concentrations above the 95th percentiles, while 3.0%-5.6% of urine levels were above 75th percentiles for at least one specific phthalate metabolite. We observed moderate intraclass correlation coefficients (ICCs) ranging from 0.44 to 0.56 for MBzP, MEHP and MEP, and lower ICCs, from 0.28 to 0.32, for MMP, MBP, MEOHP and MEHHP. Sampling season was associated with concentrations of all phthalate metabolites, showing heavier exposure was more likely to occur during summer. In summary, phthalate exposure is prevalent in Chinese pregnant women. However, throughout pregnancy coexposure to multiple phthalates at the upper percentile of exposure is infrequent. Mild to moderate temporal stability indicates that a single measurement in spot urine collected in the morning (8:00-10:00) seems not enough to describe throughout pregnancy phthalate exposure. Urinary levels vary by sampling seasons, which should be taken into consideration in future analyses.

Effect of exposure to p,p´-DDE during the first half of pregnancy in the maternal thyroid profile of female residents in a Mexican floriculture area

BACKGROUND

Dichlorodiphenyldichloroethene (p,p´-DDE), the main metabolite of dichlorodiphenyltrichloroethane (DDT), has been associated with changes in human thyroid hormone levels. Maternal thyroid hormones are essential for adequate fetal neurodevelopment during the first half of pregnancy.

OBJECTIVE

To evaluate the association between maternal p,p´-DDE concentration and the maternal thyroid profile during the first half of pregnancy.

MATERIALS AND METHODS

We analyzed the information of 430 pregnant women from a Mexican floriculture area, with a gestational age ≤16 weeks. By questionnaire, we obtained sociodemographic, reproductive, and life-style, information. Serum concentrations of thyroid stimulating hormone (TSH), and total and free T3 and T4 were determined by means of Enzyme-Linked ImmunoSorbent Assay (ELISA). p,p´-DDE was analyzed by Gas Chromatography. The association between p,p´-DDE and thyroid profile was assessed through linear and logistic regression models.

RESULTS

Thirty eight percent of women had p,p´-DDE levels below the Limit of Detection and 12.3% below the Limit of Quantification. Within the quantifiable range, median was 53.03ng/g. TSH >2.5 mIU/L was present in 9.3% of women; 47.7% had isolated hypothyroxinemia; 3.5% had subclinical hypothyroidism, and 5.8% had overt hypothyroidism. We observed a significant positive association between quantifiable p,p´-DDE and total T3 serum levels in comparison with those with concentrations below the Limit of Detection (β=0.19; 95% CI=0.06, 0.34). There were no significant associations with other hormones of the thyroid profile or with clinical diagnosis.

CONCLUSIONS

Our findings suggest that p,p´-DDE exposure, even at low concentrations, could disrupt thyroid homeostasis during pregnancy.

Contraceptive Use and Pregnancy Incidence Among Women Participating in an HIV Prevention Trial

BACKGROUND

Recent HIV prevention trials required use of effective contraceptive methods to fulfill eligibility for enrollment. We compared pregnancy rates in a subset of participants enrolled in the Microbicide Trials Network protocol (MTN-003), a randomized trial of chemoprophylaxis to prevent HIV acquisition among women aged 18-45 years who initiated depot medroxyprogesterone acetate (DMPA) or combined oral contraceptives (COCs) at enrollment, relative to those already using DMPA or COCs.

METHODS

Data were analyzed from MTN-003 participants from Uganda. Before enrollment, information on contraceptive type and initiation date was obtained. Urine pregnancy tests were performed at monthly follow-up visits. Cox proportional hazards models were used to compare pregnancy incidence among new users (initiated ≤60 days before enrollment) and established users (initiated >60 days before enrollment).

RESULTS

Of 322 women enrolled, 296 were COC or DMPA users, 82 (28%) were new users, and 214 (72%) were established users. Pregnancy incidence was higher among new contraceptive users compared to established users (20.70% vs. 10.55%; adjusted hazard ratio [HR] = 1.66; 95% confidence interval [95% CI] 0.93-2.96). Among DMPA users, pregnancy incidence was 10.20% in new users versus 3.48% in established users (HR = 2.56; 95% CI 0.86-7.65). Among new COC users, pregnancy incidence was 42.67% in new users versus 23.67% in established COC users (adjusted HR = 1.74; 95% CI 0.87-3.48).

CONCLUSIONS

New contraceptive users, regardless of method, at the Uganda MTN-003 site had an increased pregnancy risk compared to established users, which may be due to contraceptive initiation primarily for trial eligibility. New users may benefit from intensive contraceptive counseling and additional contraceptive options, including longer acting reversible contraceptives.

Distributions and determinants of urinary biomarkers of organophosphate pesticide exposure in a prospective Spanish birth cohort study

BACKGROUND

Prenatal exposure to organophosphate pesticides (OPs) has been associated with impaired child development. Pesticide exposure determinants need to be studied in order to identify sources and pathways of pesticide exposure. The aim of this paper is to describe prenatal exposure to OPs and evaluate the associated factors in pregnant women.

METHODS

The study population consisted of pregnant women (n = 573) who participated in the INMA birth cohort study in Valencia (Spain, 2003-2006). OP metabolites were analyzed in maternal urine at the 32nd week of gestation using a liquid chromatography-high resolution mass spectrometry method. The analysis included non-specific (diethyl phosphate [DEP], diethyl thiophosphate [DETP], dimethyl thiophosphate [DMTP], dimethyl dithiophosphate [DMDTP]) and specific metabolites (2-diethylamino-6-methyl-4-pyrimidinol [DEAMPY], 2-isopropyl-4-methyl-6-hydroxypyrimidine [IMPY], para-nitrophenol [PNP], and 3,5,6-trichloro-2-pyridinol [TCPY]). Information about the sociodemographic, environmental, and dietary characteristics was obtained by questionnaire. The association between log-transformed OPs and covariates was analyzed using multivariable interval censored regression.

RESULTS

The detection frequencies were low, DMTP and TCPY being the most frequently detected metabolites (53.8% and 39.1%, respectively). All the OP metabolites were positively associated with maternal intake of fruits and vegetables. Other maternal characteristics related to the OPs were body mass index (BMI) before pregnancy and smoking habit during pregnancy. Women with lower BMI and those who did not smoke presented higher OP concentrations. Moreover, mothers who had a yard or garden with plants at home or who lived in an urban area were also more exposed to OPs.

CONCLUSIONS

The OP detection frequencies and the concentrations observed in our study population were low, compared with most of the previously published studies. Given the high vulnerability of the fetus to neurotoxicant exposure, further research on the determinants of the body burden of OPs during pregnancy would be necessary. The knowledge gained from such studies would enhance the effectiveness of public health control and future recommendations in order to reduce the risk to both the health of pregnant women and the health and development of their children.

Maternal prenatal urinary phthalate metabolite concentrations and visual recognition memory among infants at 27 weeks

BACKGROUND

Prior research has demonstrated inverse associations between maternal prenatal urinary phthalate metabolite concentrations and cognitive development assessed in preschool and school-aged children. While there are a limited number of studies that evaluated these associations during infancy, no study has evaluated whether these associations exist when using the Fagan Test of Infant Intelligence (FTII), which captures novelty preference as a function of visual recognition memory.

OBJECTIVE

We evaluated associations between phthalate metabolite concentrations in maternal prenatal urine and cognition in infancy using the FTII at 27 weeks and determine if these associations are sex-specific.

METHODS

Mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBzP), monoisobutyl phthalate (MiBP), mono-ethyl phthalate (MEP), mono-3-carboxypropyl phthalate (MCPP) and four di-2-ethylhexyl phthalate metabolites (DEHP) were quantified in urine samples collected from 168 minority women living in urban neighborhoods during their third trimester of pregnancy. The FTII was administered to infants at 27 weeks to measure visual recognition memory and was recorded as the novelty preference score.

RESULTS

There were no associations between prenatal phthalate metabolite concentrations and novelty preference score in the full sample. However, there was evidence of effect modification by infant sex. Sex-stratified models demonstrated that compared to girls in the lowest tertile of MBzP concentrations, girls in tertiles 2 and 3 had, on average, 3.98 and 4.65 points lower novelty preference scores (p-value=0.04 and 0.03, respectively). The relationship was similar for ΣDEHP, MiBP, and MEP. Effects among boys were inconsistent and generally not significant.

CONCLUSION

Maternal prenatal exposure to some phthalates was negatively associated with visual recognition memory as measured by the FTII among girls at age 27 weeks.

Exposure to phytoestrogens in utero and age at menarche in a contemporary British cohort

Phytoestrogens are estrogenic compounds that occur naturally in plants. Phytoestrogens can cross the placenta, and animal studies have found associations between in utero exposure to phytoestrogens and markers of early puberty. We investigated the association between in utero exposure to phytoestrogens and early menarche (defined as <11.5 years of age at onset) using data from a nested case-control study within the Avon Longitudinal Study of Parents and Children, a longitudinal study involving families living in the South West of England. Concentrations of six phytoestrogens were measured in maternal urine samples collected during pregnancy. Logistic regression was used to explore associations between tertiles of phytoestrogen concentrations and menarche status, with adjustment for maternal age at menarche, maternal education, pre-pregnancy body mass index (BMI), child birth order, duration of breastfeeding, and gestational age at sample collection. Among 367 mother-daughter dyads, maternal median (interquartile range) creatinine-corrected concentrations (in µg/g creatinine) were: genistein 62.1 (27.1-160.9), daidzein 184.8 (88.8-383.7), equol 4.3 (2.8-9.0), O-desmethylangolensin (O-DMA) 13.0 (4.4-34.5), enterodiol 76.1 (39.1-135.8), and enterolactone 911.7 (448.1-1558.0). In analyses comparing those in the highest tertile relative to those in the lowest tertile of in utero phytoestrogen exposure, higher enterodiol levels were inversely associated with early menarche (odds ratio (OR)=0.47; 95% confidence interval (CI): 0.26-0.83), while higher O-DMA levels were associated with early menarche (OR=1.89; 95% CI: 1.04-3.42). These findings suggest that in utero exposure to phytoestrogens may be associated with earlier age at menarche, though the direction of association differs across phytoestrogens.

Variability and predictors of urinary concentrations of organophosphate flame retardant metabolites among pregnant women in Rhode Island

BACKGROUND

Organophospate flame retardants (PFRs) are chemicals of emerging concern due to restrictions on polybrominated diphenyl ether flame retardant formulations. We describe the occurrence, variability, and predictors of urinary metabolites of PFRs among pregnant women.

METHODS

In 2014-2015, 59 women from Providence, RI provided up to 3 spot urine samples during pregnancy (~12, 28, and 35 weeks' gestation). We created a pooled urine sample per woman and measured nine relevant metabolites in individual and pooled samples. We used linear mixed models to calculate intraclass correlation coefficients (ICCs) across the 3 measurements and to assess sociodemographic and dietary predictors of PFRs.

RESULTS

The median (IQR) of bis-2-chloroethyl phosphate (BCEP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), and diphenyl phosphate (DPhP), the metabolites most frequently detected, from pooled samples were: 0.31 μg/L (0.17-0.54), 1.18 μg/L (0.64-2.19), 0.93 μg/L (0.72-1.97), respectively. We observed fair to good reproducibility for BCEP (ICC = 0.50), BDCPP (ICC = 0.60), and DPhP (ICC = 0.43), and excellent agreement between the urinary flame retardant metabolite concentrations averaged across pregnancy versus pooled urine sample concentrations for BCEP (ICC = 0.95), BDCPP (ICC = 0.89), and DPhP (ICC = 0.93). Adjusting for pertinent sociodemographic factors and gestational week of urine collection, each 1 kg increase in pre-pregnancy weight was associated with greater BCEP (1.1%; 95% CI: 0.1, 2.1), BDCPP (1.5%; 95% CI: 0.3, 2.7), and DPhP (0.5%; 95% CI: 0.0, 1.1). Dietary factors were generally not associated with urinary flame retardant metabolites.

CONCLUSIONS

Urinary concentrations of BCEP, BDCPP, and DPhP were frequently detected among women in this pilot study and had fair reproducibility across pregnancy. Body size may be an important predictor of urinary flame retardant metabolite concentrations.

Urinary Concentrations of Insecticide and Herbicide Metabolites among Pregnant Women in Rural Ghana: A Pilot Study

Use of pesticides by households in rural Ghana is common for residential pest control, agricultural use, and for the reduction of vectors carrying disease. However, few data are available about exposure to pesticides among this population. Our objective was to quantify urinary concentrations of metabolites of organophosphate (OP), pyrethroid, and select herbicides during pregnancy, and to explore exposure determinants. In 2014, 17 pregnant women from rural Ghana were surveyed about household pesticide use and provided weekly first morning urine voids during three visits (n = 51 samples). A total of 90.1% (46/51) of samples had detectable OP metabolites [geometric mean, GM (95% CI): 3,5,6-trichloro-2-pyridinol 0.54 µg/L (0.36–0.81), para-nitrophenol 0.71 µg/L (0.51–1.00)], 75.5% (37/49) had detectable pyrethroid metabolites [GM: 3-phenoxybenzoic acid 0.23 µg/L (0.17, 0.32)], and 70.5% (36/51) had detectable 2,4-dichlorophenoxyacetic acid levels, a herbicide [GM: 0.46 µg/L (0.29–0.73)]. Concentrations of para-nitrophenol and 2,4-dichlorophenoxyacetic acid in Ghanaian pregnant women appear higher when compared to nonpregnant reproductive-aged women in a reference U.S. population. Larger studies are necessary to more fully explore predictors of exposure in this population.

Racial and ethnic variations in phthalate metabolite concentration changes across full-term pregnancies

Higher concentrations of certain phthalate metabolites are associated with adverse reproductive and pregnancy outcomes, as well as poor infant/child health outcomes. In non-pregnant populations, phthalate metabolite concentrations vary by race/ethnicity. Few studies have documented racial/ethnic differences between phthalate metabolite concentrations at multiple time points across the full-course of pregnancy. The objective of the study was to characterize the change in phthalate metabolite concentrations by race/ethnicity across multiple pregnancy time points. Women were participants in a prospectively collected pregnancy cohort who delivered at term (≥37 weeks) and had available urinary phthalate metabolite concentrations for ≥3 time points across full-term pregnancies (n=350 women). We assessed urinary concentrations of eight phthalate metabolites that were log-transformed and specific gravity-adjusted. We evaluated the potential racial/ethnic differences in phthalate metabolite concentrations at baseline (median 10 weeks gestation) using ANOVA and across pregnancy using linear mixed models to calculate the percent change and 95% confidence intervals adjusted for sociodemographic and lifestyle factors. Almost 30% of the population were non-Hispanic black or Hispanic. With the exception of mono-(3-carboxypropyl) (MCPP) and di-ethylhexyl phthalate (DEHP) metabolites, baseline levels of phthalate metabolites were significantly higher in non-whites (P<0.05). When evaluating patterns by race/ethnicity, mono-ethyl phthalate (MEP) and MCPP had significant percent changes across pregnancy. MEP was higher in Hispanics at baseline and decreased in mid-pregnancy but increased in late pregnancy for non-Hispanic blacks. MCPP was substantially higher in non-Hispanic blacks at baseline but decreased later in pregnancy. Across pregnancy, non-Hispanic black and Hispanic women had higher concentrations of certain phthalate metabolites. These differences may have implications for racial/ethnic differences in adverse pregnancy and child health outcomes.

Predictors of urinary flame retardant concentration among pregnant women

BACKGROUND

Organophosphate compounds are commonly used in residential furniture, electronics, and baby products as flame retardants and are also used in other consumer products as plasticizers. Although the levels of exposure biomarkers are generally higher among children and decrease with age, relatively little is known about the individual characteristics associated with higher levels of exposure. Here, we investigate urinary metabolites of several organophosphate flame retardants (PFRs) in a cohort of pregnant women to evaluate patterns of exposure.

METHODS

Pregnant North Carolina women (n=349) provided information on their individual characteristics (e.g. age and body mass index (BMI)) as a part of the Pregnancy Infection and Nutrition Study (2002-2005). Women also provided second trimester urine samples in which six PFR metabolites were measured using mass spectrometry methods.

RESULTS

PFR metabolites were detected in every urine sample, with BDCIPP, DHPH, ip-PPP and BCIPHIPP detected in >80% of samples. Geometric mean concentrations were higher than what has been reported previously for similarly-timed cohorts. Women with higher pre-pregnancy BMI tended to have higher levels of urinary metabolites. For example, those classified as obese at the start of pregnancy had ip-PPP levels that were 1.52 times as high as normal weight range women (95% confidence interval: 1.23, 1.89). Women without previous children also tended to have higher urinary levels of DPHP, but lower levels of ip-PPP. In addition, we saw strong evidence of seasonal trends in metabolite concentrations (e.g. higher DPHP, BDCIPP, and BCIPHIPP in summer, and evidence of increasing ip-PPP between 2002 and 2005).

CONCLUSIONS

Our results indicate ubiquitous exposure to PFRs among NC women in the early 2000s. Additionally, our work suggests that individual characteristics are related to exposure and that temporal variation, both seasonal and annual, may exist.

Associations of Maternal Urinary Cadmium with Trimester-Specific Blood Pressure in Pregnancy: Role of Dietary Intake of Micronutrients

Previous studies revealed associations of urinary Cd (U-Cd), a chronic Cd exposure biomarker, with blood pressure (BP) in non-pregnant adults. However, the evidence regarding trimester-specific blood pressure in pregnancy and U-Cd and effect modification by dietary intake of micronutrients is scarce. We randomly selected 653 women from the Omega Study cohort. U-Cd was quantified by inductively coupled plasma mass spectrometry. Trimester-specific, systolic (SBP) and diastolic blood pressure (DBP) were determined employing standard protocols and mean arterial pressure (MAP) was also calculated. Associations of SBP, DBP, and MAP with U-Cd tertiles (≤0.21; 0.22-0.41; ≥0.42 μg/g Cr) were assessed using multivariable linear regression models. We also explored effect modification by pre-pregnancy BMI (≤25 or >25 kg/m²) or low/high micronutrients intake. After adjusting confounders in women with elevated (upper tertile) as compared with those with low (lowest tertile) U-Cd (≥0.42 vs. ≤0.21 μg/g Cr, respectively) had reduced third trimester MAP (-1.8; 95 % confidence interval (CI) = -3.1, -0.5 mmHg) and second trimester MAP (-1.1; 95 % CI = -2.3, -0.03 mmHg). A significant decrease in third-trimester MAP associated with increased U-Cd was observed only among normal/underweight women (BMI ≤ 25 kg/m²) and women with high dietary intake of micronutrients (calcium, magnesium, zinc, and selenium). Notably, U-Cd concentrations increased with the increased consumption of zinc and non-heme iron food sources. No significant differences in U-Cd concentrations were found in preeclamptic women compared with non-preeclamptic women. Our study provides evidence that dietary intake of micronutrients should be taken into account when assessing the health effects of Cd in pregnant women.

Urinary and plasma fluoride levels in pregnant women from Mexico City

BACKGROUND

There is need to assess the developmental neurotoxicity of fluoride. Our knowledge of prenatal fluoride exposure is challenged as few population-based studies have been conducted and these generally date back several decades, provide incomplete data on sociodemographic variables, and have methodological limitations.

OBJECTIVE

To measure urinary and plasma fluoride levels across three time points in pregnant mothers who were enrolled in the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) birth cohort study.

METHODS

Fluoride levels were characterized in archived urine and plasma from 872 pregnant mothers sampled from the ELEMENT cohort. Various statistical methods were used to analyze the fluoride data with particular consideration for changes across three stages of pregnancy and against sociodemographic variables.

RESULTS

All samples had detectable levels of fluoride. The mean urinary and plasma fluoride levels were 0.91 and 0.0221mg/L respectively, and these were not statistically different across three stages of pregnancy. Fluoride levels correlated across the stages of pregnancy studied, with stronger correlations between neighboring stages. Urinary fluoride changed as pregnancy progressed with levels increasing until ~23 weeks and then decreasing until the end of pregnancy. For plasma fluoride, there was a decreasing trend but this was not of statistical significance. Creatinine-adjusted urinary fluoride levels did not associate consistently with any of the sociodemographic variables studied.

CONCLUSIONS

This study provides the most extensive characterization to date of fluoride exposure throughout pregnancy. These results provide the foundation to explore exposure-related health outcomes in the ELEMENT cohort and other studies.

Maternal phthalate exposure during early pregnancy and at delivery in relation to gestational age and size at birth: A preliminary analysis

Epidemiologic studies of in utero phthalate exposure and birth outcomes have had conflicting findings. The objective of this study was to characterize maternal phthalate exposure across pregnancy, examine associations between maternal phthalate levels and infant size and gestational age at birth, and investigate relationships between concurrent bisphenol A (BPA) and phthalate exposure and birth outcomes. Women in the Michigan Mother-Infant Pairs cohort provided urine and blood samples during their first trimester and at delivery. Urinary phthalate metabolites and serum BPA were measured at both time points, and birth weight, length, head circumference, and gestational age were recorded from medical records. Maternal DEHP metabolite concentrations were significantly higher at delivery compared to the first trimester (p<0.05), suggesting increased DEHP exposure late in pregnancy. A number of phthalate metabolites were associated with birth size and gestational age in patterns that varied by sex and timing of exposure, independent of BPA exposure.

Gestational exposure to phthalates and gender-related play behaviors in 8-year-old children: an observational study

BACKGROUND

Phthalates, used in a variety of consumer products, are a group of chemicals that are ubiquitous in the environment, and their metabolites are detectable in most humans. Some phthalates have anti-androgenic properties; a prior study reported an association between gestational exposure to phthalates and reduced masculine behaviors in preschool boys.

METHODS

Concentrations of 9 phthalate metabolites were measured in urine collected at 16 and 26 weeks' gestation from pregnant women enrolled in the HOME Study, a prospective pregnancy and birth cohort. Measures of gender-related play were collected at 8 years of age, including the Gender Identity Questionnaire (GIQ) completed by mothers, and the Playmate and Play Style Preferences Structured Interview (PPPSI) completed by children. We examined these measures as continuous variables using both bivariate and multivariable approaches with adjustment for covariates. Additional analyses included logistic regression of GIQ and PPPSI scores dichotomized by sex at the lower 25th percentile, indicating the least typical behavior.

RESULTS

Mothers' phthalate metabolite concentrations during pregnancy were similar to the reported national average among US women. All children scored within a typical range on both measures of gender-related play behavior. No statistically significant associations were found between averaged maternal phthalate metabolite concentrations and continuous PPPSI scores or any GIQ scores. For the dichotomized PPPSI; higher maternal monoethyl phthalate (MEP) concentrations were associated with more typical play behaviors for females (OR = 0.70, CI = 0.51-0.97). In contrast, higher maternal mono-isobutyl phthalate (MiBP) concentrations were associated with higher odds of membership in the least typical play behaviors group for males (OR = 1.69, CI = 1.00-2.86).

CONCLUSIONS

In this sample of typically developing children, higher maternal urinary MEP concentrations during pregnancy were associated with more typical gender-related play behaviors in both males and females, and increased urinary MiBP concentrations were associated with less masculine gender-related play behaviors in males.

Effect of Thiocyanate on Iodine Status of Pregnant Women

The aim of this study was to assess the thyroid status of pregnant women on the basis of biochemical indicators and to evaluate the potential risk of developing iodine deficiency as a result of tobacco smoke exposure by assessing the association between urinary thiocyanate levels and the manifestation of iodine deficiency. The study included 219 pregnant women from the town of Plovdiv and Plovdiv District in Southern Bulgaria. The levels of urinary iodine, thyroid-stimulating hormone (TSH), free thyroxine (FT4), and urinary thiocyanate as indicators of tobacco smoke exposure were measured. Most of the pregnant women (60.1 %) were found to have iodine deficiency, 10.6 % of them had TSH values greater than 4 mIU/L, and 16.4 % had FT4 below 9 pmol/L. There were negative correlations between urinary iodine levels and thiocyanate/creatinine ratio (R = -0.148, р = 0.034) and between thiocyanate/creatinine ratio and FT4 (R = -0.379, p < 0.0001); thiocyanate/creatinine ratio and serum TSH were positively correlated (R = 0.169, p = 0.019). Logistic regression analysis showed that pregnant women in whom the thiocyanate/creatinine ratio was greater than the median value of 3.57 mg/g had a 3.882-fold higher risk of developing iodine deficiency (urinary iodine <150 μg/L) than the pregnant women with lower thiocyanate levels (OR = 3.882, 95 % CI 1.402-10.751, p = 0.009). Higher levels of urinary thiocyanate were found in women exposed to tobacco smoke, and quantification of these ions in urine provided a fast non-invasive method to monitor thiocyanate load. Due to the competitive inhibition of iodine intake by thiocyanates, their levels should be carefully monitored, especially in cases of severe iodine deficiency.

Assessment of Exposure to VOCs among Pregnant Women in the National Children's Study

Epidemiologic studies can measure exposure to volatile organic compounds (VOCs) using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children's Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS). We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking) and by observations by a trained data collector (presence of scented products in homes). We found several significant (p < 0.01) relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite N-acetyl-S-(benzyl)-L-cysteine (BMA), and paint use was positively associated with the xylene metabolites 2-methylhippuric acid (2MHA) and 3-Methylhippuric acid & 4-methylhippuric acid (3MHA + 4MHA). A near-significant (p = 0.06) relationship was observed between acrylamide metabolites and observation of incense.

Iodine status of pregnant women in a metropolitan city which proved to be an iodine-sufficient area. Is mandatory salt iodisation enough for pregnant women?

The objective of this study was to assess the iodine status of pregnant women in a metropolitan city which was stated as iodine sufficient area after salt iodination program. This multicenter, cross-sectional study was carried out on 3543 pregnant women. Age, gestational weeks, smoking, consumption of iodized salt, dietary salt restriction, history of stillbirth, abortus and congenital malformations were questioned. Spot urine samples were analyzed for urine iodine concentration (UIC). The outcomes were: (a) median UIC in three trimesters of pregnancy and (b) frequency of ID among pregnant women. The median UIC was 73 µg/L. The median UIC was 77 µg/L (1-324), 73 µg/L (1-600) and 70 µg/L (1-1650) in three trimesters of pregnancy, respectively (p: 0.14). UIC <50 µg/L was observed in 36.6% (n: 1295) and UIC<150 µg/L was observed in 90.7% (n: 3214) of pregnant women. Only 1% (n: 34) of the pregnant women had UIC levels higher than 500 µg/L. This study showed that more than 90% of the pregnant women in this iodine-sufficient city are facing some degree of iodine deficiency during their pregnancy. A salt iodization program might be satisfactory for the non-pregnant population, but it seems to be insufficient for the pregnant population.

Placental arsenic concentrations in relation to both maternal and infant biomarkers of exposure in a US cohort

Arsenic crosses the placenta and may have adverse consequences in utero and later in life. At present, little is known about arsenic concentrations in placenta and their relation to maternal and infant exposures particularly at common levels of exposure. We measured placenta arsenic in a US cohort potentially exposed via drinking water from private wells, and evaluated the relationships between placenta and maternal and infant biomarker arsenic concentrations. We measured total arsenic concentrations in placental samples from women enrolled in the New Hampshire Birth Cohort Study (N=766). We compared these data to maternal urinary arsenic (total arsenic and individual species) collected at approximately 24-28 week gestation, along with maternal post-partum toenails and infant toenails using non-parametric multivariate analysis of log10-transformed data. We also examined the association between placental arsenic and household drinking water arsenic. Placenta arsenic concentrations were related to arsenic concentrations in maternal urine (β 0.55, P value <0.0001), maternal (β 0.30, P value 0.0196) and infant toenails (β 0.40, P value 0.0293) and household drinking water (β 0.09, P value <0.0001). Thus, our data suggest that placenta arsenic concentrations reflect both maternal and infant exposures.

Arsenic exposure and hepatitis E virus infection during pregnancy

BACKGROUND

Arsenic has immunomodulatory properties and may have the potential to alter susceptibility to infection in humans.

OBJECTIVES

We aimed to assess the relation of arsenic exposure during pregnancy with immune function and hepatitis E virus (HEV) infection, defined as seroconversion during pregnancy and postpartum.

METHODS

We assessed IgG seroconversion to HEV between 1st and 3rd trimester (TM) and 3 months postpartum (PP) among 1100 pregnancies in a multiple micronutrient supplementation trial in rural Bangladesh. Forty women seroconverted to HEV and were matched with 40 non-seroconverting women (controls) by age, parity and intervention. We assessed urinary inorganic arsenic plus methylated species (∑As) (µg/L) at 1st and 3rd TM and plasma cytokines (pg/mL) at 1st and 3rd TM and 3 months PP.

RESULTS

HEV seroconverters' urinary ∑As was elevated throughout pregnancy. Non-seroconverters' urinary ∑As was similar to HEV seroconverters at 1st TM but declined at 3rd TM. The adjusted odds ratio (95% confidence interval) of HEV seroconversion was 2.17 (1.07, 4.39) per interquartile range (IQR) increase in average-pregnancy urinary ∑As. Increased urinary ∑As was associated with increased concentrations of IL-2 during the 1st and 3rd TM and 3 months PP among HEV seroconverters but not non-seroconverters.

CONCLUSIONS

The relation of urinary arsenic during pregnancy with incident HEV seroconversion and with IL-2 levels among HEV-seroconverting pregnant women suggests arsenic exposure during pregnancy may enhance susceptibility to HEV infection.

Gestation-specific reference intervals for comprehensive spot urinary steroid hormone metabolite analysis in normal singleton pregnancy and 6 weeks postpartum

BACKGROUND

Normal pregnancy depends on pronounced adaptations in steroid hormone concentrations. Although in recent years, the understanding of these hormones in pregnancy has improved, the interpretation is hampered by insufficient reference values. Our aim was to establish gestation-specific reference intervals for spot urinary steroid hormone levels in normal singleton pregnancies and 6 weeks postpartum.

METHODS

Cross-sectional multicentre observational study. Women recruited between 2008 and 2013 at 3 University Hospitals in Switzerland (Bern), Scotland (Glasgow) and Austria (Graz). Spot urine was collected from healthy women undergoing a normal pregnancy (age, 16-45 years; mean, 31 years) attending routine antenatal clinics at gestation weeks 11, 20, and 28 and approximately 6 weeks postpartum. Urine steroid hormone levels were analysed using gas-chromatography mass spectrometry. Creatinine was also measured by routine analysis and used for normalisation.

RESULTS

From the results, a reference interval was calculated for each hormone metabolite at each trimester and 6 weeks postpartum. Changes in these concentrations between trimesters and postpartum were also observed for several steroid hormones and followed changes proposed for index steroid hormones.

CONCLUSIONS

Normal gestation-specific reference values for spot urinary steroid hormones throughout pregnancy and early postpartum are now available to facilitate clinical management and research approaches to steroid hormone metabolism in pregnancy and the early postpartum period.

Maternal exposure to alkali, alkali earth, transition and other metals: Concentrations and predictors of exposure

Most studies of metals exposure focus on the heavy metals. There are many other metals (the transition, alkali and alkaline earth metals in particular) in common use in electronics, defense industries, emitted via combustion and which are naturally present in the environment, that have received limited attention in terms of human exposure. We analysed samples of whole blood (172), urine (173) and drinking water (172) for antimony, beryllium, bismuth, cesium, gallium, rubidium, silver, strontium, thallium, thorium and vanadium using ICPMS. In general most metals concentrations were low and below the analytical limit of detection with some high concentrations observed. Few factors examined in regression models were shown to influence biological metals concentrations and explained little of the variation. Further study is required to establish the source of metals exposures at the high end of the ranges of concentrations measured and the potential for any adverse health impacts in children.

Relationship of urinary phthalate metabolites with serum thyroid hormones in pregnant women and their newborns: a prospective birth cohort in Taiwan

Background

The purpose of this study was to examine the relationship of phthalates exposure with thyroid function in pregnant women and their newborns.

Methods

One hundred and forty-eight Taiwanese maternal and infant pairs were recruited from E-Da hospital in southern Taiwan between 2009 and 2010 for analysis. One-spot urine samples and blood samples in the third trimester of pregnant women and their cord blood samples at delivery were collected. Nine phthalate metabolites in urine were determined by triple quadrupole liquid chromatography tandem mass spectrometry, whereas serum from pregnant women and their cord blood were used to measure thyroid profiles (thyroid-stimulating hormone [TSH], thyroxine, free thyroxine, and triiodothyronine) by radioimmunoassay.

Results

Median levels of urinary mono-n-butyl phthalate, mono-ethyl phthalate, and mono-(2-ethyl-5-oxohexyl) phthalate (μg/g creatinine) were the three highest phthalate metabolites, which were 37.81, 34.51, and 21.73, respectively. Using Bonferroni correction at a significance of < 0.006, we found that urinary mono-benzyl phthalate (MBzP) levels were significantly and negatively associated with serum TSH in cord blood (β = -2.644, p = 0.003).

Conclusions

Maternal urinary MBzP, of which the parental compound is butylbenzyl phthalate, may affect TSH activity in newborns. The alteration of thyroid homeostasis by certain phthalates in the early life, a critical period for neurodevelopment, is an urgent concern.

Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R Study

The widespread use of organophosphate (OP) pesticides has resulted in ubiquitous exposure in humans, primarily through their diet. Exposure to OP pesticides may have adverse health effects, including neurobehavioral deficits in children. The optimal design of new studies requires data on the reliability of urinary measures of exposure. In the present study, urinary concentrations of six dialkyl phosphate (DAP) metabolites, the main urinary metabolites of OP pesticides, were determined in 120 pregnant women participating in the Generation R Study in Rotterdam. Intra-class correlation coefficients (ICCs) across serial urine specimens taken at <18, 18-25, and >25 weeks of pregnancy were determined to assess reliability. Geometric mean total DAP metabolite concentrations were 229 (GSD 2.2), 240 (GSD 2.1), and 224 (GSD 2.2) nmol/g creatinine across the three periods of gestation. Metabolite concentrations from the serial urine specimens in general correlated moderately. The ICCs for the six DAP metabolites ranged from 0.14 to 0.38 (0.30 for total DAPs), indicating weak to moderate reliability. Although the DAP metabolite levels observed in this study are slightly higher and slightly more correlated than in previous studies, the low to moderate reliability indicates a high degree of within-person variability, which presents challenges for designing well-powered epidemiological studies.

Bisphenol A and phthalate metabolite urinary concentrations: Daily and across pregnancy variability

Phthalates and bisphenol A (BPA) are high production volume and ubiquitous chemicals that are quickly metabolized in the body. Traditionally, studies have relied on single spot urine analyses to assess exposure; ignoring variability in concentrations throughout a day or over a longer period of time. We compared BPA and phthalate metabolite results from urine samples collected at five different time points. Participants (n=80) were asked to collect all voids in a 24 h period on a weekday and then again on a weekend before 20 weeks of pregnancy. During the second and third trimesters and in the postpartum period, single spot urines were collected. Variability over time in urinary concentrations was assessed using intraclass correlation coefficients (ICCs) and the sensitivity to correctly classify a single sample as high or low versus the geometric mean (GM) of all samples was calculated. We found low reproducibility and sensitivity of BPA and all phthalate metabolites throughout pregnancy and into the postpartum period but much higher reproducibility within a day. Time of day when the urine was collected was a significant predictor of specific gravity adjusted exposure levels. We concluded that, if the interest is in average exposures across pregnancy, maternal/fetal exposure estimation may be more accurate if multiple measurements, collected across the course of the entire pregnancy, rather than a single spot measure, are performed.

Urinary phthalate metabolites in relation to maternal serum thyroid and sex hormone levels during pregnancy: a longitudinal analysis

BACKGROUND

Increasing scientific evidence suggests that exposure to phthalates during pregnancy may be associated with an elevated risk of adverse reproductive outcomes such as preterm birth. Maternal endocrine disruption across pregnancy may be one pathway mediating some of these relationships. We investigated whether urinary phthalate metabolites were associated with maternal serum thyroid (free thyroxine [FT4], free triiodothyronine [FT3], and thyroid-stimulating hormone [TSH]), and sex (estradiol, progesterone, and sex hormone-binding globulin [SHBG]) hormone levels at multiple time points during pregnancy.

METHODS

Preliminary data (n = 106) were obtained from an ongoing prospective birth cohort in Northern Puerto Rico. We collected urine and serum sample at the first and third study visits that occurred at 18 +/- 2 and 26 +/- 2 weeks of gestation, respectively. To explore the longitudinal relationships between urinary phthalate metabolites and serum thyroid and sex hormone concentrations, we used linear mixed models (LMMs) adjusted for prepregnancy body mass index (BMI) and maternal age. An interaction term was added to each LMM to test whether the effect of urinary phthalate metabolites on serum thyroid and sex hormone levels varied by study visit. In cross-sectional analyses, we stratified BMI- and age-adjusted linear regression models by study visit.

RESULTS

In adjusted LMMs, we observed significant inverse associations between mono-3-carboxypropyl phthalate (MCPP) and FT3 and between mono-ethyl phthalate (MEP) and progesterone. In cross-sectional analyses by study visit, we detected stronger and statistically significant inverse associations at the third study visit between FT3 and MCPP as well as mono-carboxyisooctyl phthalate (MCOP); also at the third study visit, significant inverse associations were observed between FT4 and metabolites of di-(2-ethylhexyl) phthalate (DEHP). The inverse association between MEP and progesterone was consistent across study visits.

CONCLUSIONS

In this group of pregnant women, urinary phthalate metabolites may be associated with altered maternal serum thyroid and sex hormone levels, and the magnitude of these effects may depend on the timing of exposure during gestation.

[Sufficiency with water-soluble vitamins and state of bone in pregnant women]

Vitamin status and bone strength have been estimated in 91 pregnant women (29.3 ± 4.6 years old) from Moscow by non-invasive methods. Sufficiency with vitamins C, B2, B6 has been evaluated by morning urinary excretion of ascorbic acid, riboflavin and 4-piridoxic acid determined by visual titration and fluorimetric methods. The rate of bone resorption has been measured by the ratio of urinary calcium and creatinine, determined by complexometric titration and spectrophotometrically. The study of the bone strength has been conducted using an ultrasonic densitometer (the speed of the ultrasonic waves along the cortical layer). The lack of vitamin C was found in 20.4% .of the women surveyed, vitamin B2--in 27.4%. Vitamin B6 deficiency was detected most frequently (90%). Excretion of vitamins B2 and B6 in women in the third trimester of pregnancy was lower as compared with the women in the first and second trimester. In 53.3% of the women surveyed an increase in urinary excretion of calcium per creatinine has been observed. Excretion of group B vitamins (especially vitamin B6, 1.75 fold, p < 0.05) in women taking vitamin supplements was higher compared to non-taking vitamins that indicates the better sufficiency of the organism with these vitamins. Among women who took vitamin complexes, inadequate supply with water-soluble vitamins C, B2 and B6 was detected less frequently (the difference was significant for vitamin B2) than among women who did not intake vitamin complexes (in 11.9, 27.7 and 42.4% vs 16.1, 54.8 and 48.8 %). The rate of bone resorption (Ca/creatinine) in women taking vitamins was smaller (0.19 ± 0.09 vs 0.24 ± 0.14, p > 0.05). Ca/creatinine ratio was within normal range in 40% of women who intake vitamins, while in women not taking vitamins--only in 22.2%; this value exceeded the upper limit of norm in the rest. The strength of bone was broken in women in the second and third trimester of pregnancy, having worse supply of vitamins. The percentage of agreement of the results of osteopenia diagnosis assessment (ultrasound densitometry and urinary Ca/creatinine) was 42.2%. Thus, the conclusion has been confirmed that the evaluation of the status of bone is possible only basing on the results of determination of several parameters.

A device architecture for three-dimensional, patterned paper immunoassays

Diagnostic assays can provide valuable information about the health status of a patient, which include detection of biomarkers that indicate the presence of an infection, the progression or regression of a disease, and the efficacy of a course of treatment. Critical healthcare decisions must often be made at the point-of-care, far from the infrastructure and diagnostic capabilities of centralized laboratories. There exists an obvious need for diagnostic tools that are designed to address the unique challenges encountered by healthcare workers in limited-resource settings. Paper, a readily-available and inexpensive commodity, is an attractive medium with which to develop diagnostic assays for use in limited-resource settings. In this article, we describe a device architecture to perform immunoassays in patterned paper. These paper-based devices use a combination of lateral and vertical flow to control the wicking of fluid in three-dimensions. We provide guidelines to aid in the design of these devices and we illustrate how patterning can be used to tune the duration and performance of the assay. We demonstrate the use of these paper-based devices by developing a sandwich immunoassay for human chorionic gonadotropin (hCG) in urine, a biomarker of pregnancy. We then directly compare the qualitative and quantitative results of these paper-based immunoassays to commercially available lateral flow tests (i.e., the home pregnancy test). Our results suggest paper-based devices may find broad utility in the development of immunoassays for use at the point-of-care.