Serum Concentrations of Selected Poly- and Perfluoroalkyl Substances (PFASs) in Pregnant Women and Associations with Birth Outcomes. A Cross-Sectional Study from Southern Malawi

Association of prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances with fetal growth trajectories

BACKGROUND

Maternal perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure during pregnancy is linked to adverse birth outcomes; however, its impact on fetal growth trajectories remains unclear.

OBJECTIVE

To examine the relationship between prenatal PFAS exposure and fetal growth trajectories.

METHODS

We included 352 mother-infant pairs from a prospective study conducted at Changsha Hospital for Maternal and Child Health Care, Hunan Province, China. Maternal blood samples at 11-13 weeks gestation were analyzed for 25 PFAS. Fetal growth indicators-estimated fetal weight (EFW), biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL)-were measured at 14-41 weeks of gestation and expressed as Z-scores using INTERGROWTH-21st standards. Linear mixed-effects models assessed associations between PFAS levels and growth trajectories, with subgroup analyses performed by infant sex.

RESULTS

Early pregnancy perfluorooctanoic acid (PFOA) concentration was negatively associated with EFW (β = -0.17, 95% confidence interval [CI]: -0.33, -0.01) Z-scores, perfluorodecanoic acid (PFDA) concentration was negatively associated with BPD (β = -0.13, 95% CI: -0.26, -0.002) and AC (β = -0.12 95% CI: -0.23, -0.004) Z-scores; perfluoroundecanoic acid (PFUdA) concentration was negatively associated with EFW (β = -0.14, 95% CI: -0.26, -0.02) and BPD (β = -0.18, 95% CI: -0.30, -0.06) Z-scores, perfluorooctane sulfonic acid (PFOS) concentration was negatively associated with AC (β = -0.13, 95% CI: -0.25, -0.01) Z-scores. In contrast, N-ethylperfluoro-1-octanesulfonamide (N-EtFOSA-M) concentration was positively associated with EFW (β = 0.11, 95% CI: 0.02, 0.19), BPD (β = 0.11, 95% CI: 0.02, 0.20) and FL (β = 0.13, 95% CI: 0.04, 0.22) Z-scores and potassium11-chloroeicosafluoro-3-oxaundecane-I-sulfonate (8:2CI-PFESA) concentration was positively associated with HC (β = 0.08, 95% CI: 0.004, 0.16) Z-scores. Subgroup analyses revealed that PFDA, PFUdA, and perfluorotridecanoic acid (PFTrDA) concentrations were negatively associated with EFW Z-scores in female infants, and 8:2CI-PFESA concentrations was positively associated with HC and FL Z-scores in male infants.

CONCLUSION

Legacy PFAS exposure may impede fetal growth, especially in female infants; whereas, novel PFAS may be positively associated with fetal growth, particularly in male infants.

Assessing the impact of per- and polyfluoroalkyl substances on pregnancy loss: An environmental-wide association study in Northwest China

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are emerging environmental contaminants with potential metabolic and endocrine-disrupting properties that may affect women's reproductive health. However, their specific role in pregnancy loss remains relatively understudied.

OBJECTIVES

This study aimed to assess the association between exposure to multiple PFAS and the association with pregnancy loss (PL) in a population from Northwest China using an environment-wide association study (EWAS) approach.

METHODS

A case-control study was conducted at a university-affiliated reproductive center, enrolling 348 women with a history of PL and 320 controls with at least one live birth and no history of pregnancy loss. Serum concentrations of ten PFAS were quantified using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) following a standardized extraction and purification protocol. Demographic and clinical data were collected via a structured questionnaire. An elastic net regression model (ENRM) was employed for variable selection, identifying PFASs to be included in the subsequent EWAS analysis. Associations between individual PFAS and PL were then evaluated using logistic regression, and EWAS was utilized to explore the overall associations between PFAS mixture exposure and PL, accounting for potential interactions and multicollinearity.

RESULTS

The EWAS identified five PFASs-PFPeS, PFHxS, PFOA, PFOS, and PFNA-with significantly higher exposure odds in pregnancy loss cases versus live birth controls (adjusted ORs: 1.82 [1.31-2.62], 1.34 [1.19-1.51], 1.73 [1.46-2.07], 1.33 [1.14-1.56], and 1.73 [1.40-2.15], respectively). Subgroup analyses confirmed robust associations, with PFOA consistently linked to elevated exposure odds across demographic and clinical strata.

CONCLUSION

This study demonstrates a significant association between exposure to multiple PFAS, notably PFPeS, PFHxS, PFOA, PFOS, and PFNA, and an increased risk of pregnancy loss in a Northwest Chinese population. The particularly robust association observed with PFOA across diverse subgroups underscores its potential as a significant environmental risk factor for PL. These findings highlight the need for further research to elucidate the underlying mechanisms and to develop strategies for reducing PFAS exposure among women of reproductive age.

Maternal per- and polyfluoroalkyl substances exposure, cord blood lipidomics and infant anthropometry: A mediation analysis

Maternal exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with offspring adiposity; however, underlying mechanisms remain unclear. In this study, we quantified 11 PFAS in maternal plasma collected between 12 and 16 gestational weeks and 104 lipid metabolites in the cord blood of 525 mother-infant pairs. Principal components of multiple PFAS compounds, extracted by principal component analysis, were employed to investigate the effect of the PFAS mixture. Infant anthropometric indicators included weight, length, waist/arm circumference, and abdominal/triceps/subscapular skinfold thickness at birth and 6 and 12 months old. Multiple linear regression showed that maternal PFAS exposure was primarily associated with increased glycerophospholipids and decreased fatty acyls and bile acids in cord blood. Four glycerophospholipids (16:0 PI, 16:0-18:1 PI, 18:0-20:4 PI, and 18:0-18:1 PS), fatty acyls (5(S)-HETE, 15(S)-HETE, 13-HDoHE, and dhkPGF2), and bile acids (GCA, TCA, TCDA, and TDCA) partially mediated the positive associations of the first principle component of PFAS compounds (with positive loadings for all PFAS compounds), PFNA, and PFUdA with infant skinfold thickness with mediating proportions ranging from 15.24% to 33.39%. Our findings provide novel insights into mechanisms underlying the effects of maternal PFAS exposure on infant growth.

Concentrations of potentially toxic metals and trace elements in pregnant women and association with birth outcomes: A cross-sectional study in Malawi

Potentially toxic metals and trace elements have been used in Malawi for a long time. However, data on exposure to these elements by susceptible groups like pregnant women and its associations with reproductive health outcomes in Malawi and southern hemisphere is limited. We investigated the concentrations of potentially toxic metals as well as trace elements in pregnant women and assessed the relationship between the levels these elements in maternal blood and sociodemographic factors, dietary habits and birth outcomes. Maternal data was collected from 605 pregnant women. Provider administered questionnaire was used to collect data on maternal sociodemographic factors, life style and immediate birth outcomes. Maternal venous blood samples were collected from 506 pregnant women in southern Malawi between August 2020 and July 2021. An inductively coupled plasma mass spectrometry (ICP-MS) technique was used to analyse maternal blood samples for concentrations of arsenic (As), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se) and zinc (Zn). Maternal age emerged as the primary predictor for Cu (p = 0.023), As (p = 0.034) and Hg (p = 0.013) blood concentrations, followed by area of residence, which had significant impact on Ni (p = 0.024) and As (p < 0.001) concentrations. High maternal blood concentrations of Ni were associated with increased birth weight (p = 0.047), birth length (p = 0.026), head circumference (p = 0.029) and gestational age (p = 0.035). Negative associations were observed between maternal whole blood total arsenic (combining organic and inorganic As) concentration and neonatal birth length (p = 0.048) and head circumferences (p < 0.001). Similarly, higher maternal blood Pb concentrations were associated with smaller head circumference (p = 0.002) and birth weight (p = 0.016). This study demonstrates the need to introduce biomonitoring studies in Malawi and countries with similar settings in the global south.

Sex, age, and species differences of perfluorooctanoic acid modeled by flow- versus permeability-limited physiologically-based pharmacokinetic models

This study aimed to investigate sex, age, and species differences of perfluorooctanoic acid (PFOA) using physiologically-based pharmacokinetic (PBPK) models in rats and humans. PBPK models were generally developed as either flow- or permeability-limited models. The flow-limited model is cost-effective and allows for human PK prediction through simple allometric scaling, while the permeability-limited model can incorporate detailed information on the disposition process through in vitro-in vivo extrapolation (IVIVE). PFOA was administered via oral or intravenous administration with 5 mg/kg in male and female rats of different ages and the data was used to develop the PBPK models. Our results showed that both models successfully captured sex differences in rats, while only the flow-limited model with male rats and the permeability-limited model with both male and female rats provided comparable predictions in the human clinical study. More than the flow-limited model, the permeability-limited model effectively explained sex differences in rats and species differences through IVIVE. Additionally, the ontogeny-based mechanistic description of PFOA disposition enabled the interpretation of age- and sex-dependent pharmacokinetics. Although the flow-limited PBPK model lacked mechanistic interpretability compared to the permeability-limited model, it demonstrated reliable human prediction through simple allometric scaling. In conclusion, the permeability PBPK model could interpret age, sex, and species differences and it could improve the accuracy of human prediction.

PFAS alters placental arterial vasculature in term human placentae: A prospective pregnancy cohort study

INTRODUCTION

Perfluoroalkyl substances (PFAS) are synthetic chemicals used in industrial and consumer goods that are widely detected in human populations and are associated with adverse health outcomes, including perinatal health risks and child health. One mechanism of influence may be the impact of PFAS exposure on placental structure and function.

OBJECTIVES

The objective of this study is to investigate the relationship between maternal prenatal exposure to PFAS and measures of placental vascularization, and to assess whether changes in vascularization play a role in mediating the impact of PFAS on birth outcomes.

METHODS

Using data from a prospective cohort study, we examined associations between second trimester PFAS (individually and as mixtures using Bayesian kernel machine regression) and placental arterial vasculature in term placentae (N = 158); secondarily we evaluated the degree to which alterations in placental arterial vasculature explained associations between PFAS exposure and birth outcomes. Placental arterial vasculature features were collected from arterial tracings of each placental image.

RESULTS

In both linear regression and mixture models, natural log-transformed perfluorooctanoic acid concentrations were negatively associated with surface vasculature, indexed by the mean distance from arterial end point to perimeter (β = -0.23, 95% CI: -0.41, -0.041); additionally, maximum arterial tortuosity was negatively associated with placental weight (β = -0.19, 95% CI: -0.34, -0.051). There were no reliable differences in effect by fetal sex.

DISCUSSION

The findings provide some of the first evidence of PFAS exposure shaping a key measure of placental vascular function, which may underlie the impact of PFAS on perinatal and child health risks.

Predictors of Maternal Serum Concentrations for Selected Persistent Organic Pollutants (POPs) in Pregnant Women and Associations with Birth Outcomes: A Cross-Sectional Study from Southern Malawi

Population exposure to persistent organic pollutants (POPs) may result in detrimental health effects, especially to pregnant women, developing foetuses and young children. We are reporting the findings of a cross-sectional study of 605 mothers in their late pregnancy, recruited between August 2020 and July 2021 in southern Malawi, and their offspring. The aim was to measure the concentrations of selected POPs in their maternal serum and indicate associations with social demographic characteristics and birth outcomes. A high level of education was the main predictor of p,p'-DDE (p = 0.008), p,p'-DDT (p < 0.001), cis-NC (p = 0.014), o,p'-DDT (p = 0.019) and o,p'-DDE (p = 0.019) concentrations in maternal serum. Multiparity was negatively associated with o,p'-DDE (p = 0.021) concentrations. Maternal age was also positively associated (p,p'-DDE (p = 0.013), o,p'-DDT (p = 0.017) and o,p'-DDE (p = 0.045) concentrations. Living in rural areas was inversely associated with high maternal serum concentrations of p,p'-DDT (p < 0.001). Gestational age was positively associated with p,p'-DDE (p = 0.031), p,p'-DDT (p = 0.010) and o,p'-DDT (p = 0.022) concentrations. Lastly, an inverse association was observed between head circumference and t-NC (p = 0.044), Oxychlordane (p = 0.01) and cis-NC (p = 0.048). These results highlight the need to continue monitoring levels of POPs among vulnerable populations in the southern hemisphere.