Prenatal exposure to organophosphate and pyrethroid insecticides and the herbicide 2,4-dichlorophenoxyacetic acid and size at birth in urban pregnant women

Prenatal exposure to ethion caused maternal and foetal toxicity in rats

Ethion is a class II moderately toxic organothiophosphate pesticide. The main objective of this study was to evaluate the maternal and foetal toxicity of ethion in rats. Pregnant rats were divided into 5 groups. Group I served as control. Group II, III, IV, and V were orally administered with 0.86, 1.71, 3.43, and 6.9 mg/kg of ethion respectively, from gestational day (GD) 6-19. Dams were sacrificed on GD 20. Maternal toxicity was assessed by body weight gain, foetal resorptions, oxidative stress, liver and kidney function tests, and histopathology. Foetal toxicity was assessed by physical status, gross, teratological and histopathological examination. Ethion caused dose-dependent reduction in maternal body weight gain, increased resorptions, and reduced gravid uterine weights. Elevated MDA levels and altered levels of GSH, SOD and catalase were recorded in pregnant dam serum and tissues. SGOT, SGPT, total bilirubin, urea, uric acid, and creatinine were elevated in ethion groups indicating liver and kidney toxicity. Histology of uterus revealed myometrial degeneration and mucosal gland atrophy in uterus of pregnant dams and degenerative changes in placenta. It showed histological alterations in liver, kidney, and lungs. There was reduction in the foetal body weights and placental weights, and degenerative changes in the foetal liver and kidney. Gross evaluation of foetuses showed subcutaneous hematoma. Skeletal evaluation showed partial ossification of skull bones, costal separation, and agenesis of tail vertebrae, sternebrae, metacarpals and metatarsals. The findings reveal that prenatal exposure to ethion caused maternal and foetal toxicity in rats.

Pesticide exposure, birth size, and gestational age in the ISA birth cohort, Costa Rica

Purpose

To examine associations of prenatal biomarkers of pesticide exposure with birth size measures and length of gestation among newborns from the Infants' Environmental Health (ISA) birth cohort, Costa Rica.

Methods

We included 386 singleton liveborn newborns with data on birth size measures, length of gestation, and maternal urinary biomarkers of chlorpyrifos, synthetic pyrethroids, mancozeb, pyrimethanil, and 2, 4-D during pregnancy. We associated biomarkers of exposure with birth outcomes using multivariate linear regression and generalized additive models.

Results

Concentrations were highest for ethylene thiourea (ETU, metabolite of mancozeb), median = 3.40; p10-90 = 1.90-6.79 µg/L, followed by 3,5,6-trichloro-2-pyridinol (TCP, metabolite of chlorpyrifos) p50 = 1.76 p10-90 = 0.97-4.36 µg/L, and lowest for 2,4-D (p50 = 0.33 p10-90 = 0.18-1.07 µg/L). Among term newborns (≥37 weeks), higher prenatal TCP was associated with lower birth weight and smaller head circumference (e.g., β per 10-fold-increase) during the second half of pregnancy = -129.6 (95% confidence interval [CI] = -255.8, -3.5) grams, and -0.61 (95% CI = -1.05, -0.17) centimeters, respectively. Also, among term newborns, prenatal 2,4-D was associated with lower birth weight (β per 10-fold-increase = -125.1; 95% CI = -228.8, -21.5), smaller head circumference (β = -0.41; 95% CI = -0.78, -0.03), and, during the second half of pregnancy, with shorter body length (β = -0.58; 95% CI = -1.09, -0.07). Furthermore, ETU was nonlinearly associated with head circumference during the second half of pregnancy. Biomarkers of pyrethroids and pyrimethanil were not associated with birth size, and none of the biomarkers explained the length of gestation.

Conclusions

Prenatal exposure to chlorpyrifos and 2,4-D, and, possibly, mancozeb/ETU, may impair fetal growth.

Associations of maternal exposure to 2,4-dichlorophenoxyacetic acid during early pregnancy with steroid hormones among one-month-old infants

BACKGROUND

Exposure to 2,4-dichlorophenoxyacetic acid (2,4-D), a widely used hormonal herbicide, may disrupt steroid hormone homeostasis. However, evidence from population-based studies is limited, especially for one-month-old infants whose steroid hormones are in a state of adjustment to extrauterine life and can be important indicators of endocrine development. This study aimed to explore the associations between maternal 2,4-D exposure during early pregnancy and infant steroid hormone levels.

METHODS

The 885 mother-infant pairs were from a birth cohort in Wuhan, China. Maternal exposure to 2,4-D was determined in urine samples from early pregnancy, and nine steroid hormones were determined in infant urine. The associations of maternal 2,4-D exposure with infant steroid hormones and their product-to-precursor ratios were estimated based on generalized linear models, and bioinformatic analysis was conducted with public databases to explore the potential mechanisms involved.

RESULTS

The detection frequency of 2,4-D was 99.32 %, and the detection frequency of steroid hormones ranged from 98.42 % to 100.00 %. After adjusting for covariates, an interquartile range increase in 2,4-D concentrations was associated with a 7.84 % decrease in 11-deoxycortisol (95 % confidence interval, CI: -14.12 %, -1.10 %), an 8.09 % decrease in corticosterone (95 % CI: -14.56 %, -1.14 %), an 8.67 % decrease in cortisol (95 % CI: -14.43 %, -2.52 %), a 13.00 % decrease in cortisone (95 % CI: -20.64 %, -4.62 %), and an 11.17 % decrease in aldosterone (95 % CI: -19.62 %, -1.83 %). Maternal 2,4-D was also associated with lower infant cortisol/17α-OH-progesterone, cortisol/pregnenolone, and aldosterone/pregnenolone ratios. In bioinformatic analysis, pathways/biological processes related to steroid hormone synthesis and secretion were enriched from target genes of 2,4-D exposure.

CONCLUSIONS

Maternal urinary 2,4-D during early pregnancy was associated with lower infant urinary 11-deoxycortisol, corticosterone, cortisol, cortisone, and aldosterone, reflecting that 2,4-D exposure may interfere with infant steroid hormone homeostasis. Further efforts are still needed to study the relevant health effects of exposure to 2,4-D, particularly for vulnerable populations.

Effect of prenatal exposure to organophosphates and pyrethroid pesticides on neonatal anthropometric measures and gestational age

Several studies have examined the association between prenatal exposure to organophosphate and pyrethroid pesticides and their impact on foetal growth and newborn anthropometry; however, the available evidence is limited and inconclusive. This study examined whether prenatal organophosphate and pyrethroid pesticide exposure was associated with anthropometric measures at birth (weight, length, head circumference), ponderal index, gestational age, and prematurity in 537 mother-child pairs. These were randomly selected from the 800 pairs participating in the prospective birth cohort GENEIDA (Genetics, early life environmental exposures and infant development in Andalusia). Six non-specific organophosphate metabolites (dialkylphosphates, DAPs), one metabolite relatively specific to chlorpyrifos (3,5,6-trichloro-2-pyridinol, TCPy) and a common metabolite to several pyrethroids (3-phenoxybenzoic acid, 3-PBA) were measured in maternal urine from the 1st and 3rd pregnancy trimesters. Information on anthropometric measures at birth, gestational age and prematurity was retrieved from medical records. The sum on a molar basis of DAPs with methyl (ƩDMs) and ethyl (ƩDEs) moieties and the sum of the 6 DAPs metabolites (ƩDAPs) was calculated for both trimesters of pregnancy. High urinary levels of dimethyl phosphate (DMP) during the 3rd trimester were associated with a decrease in birth weight (β = -0.24; 95% CI: 0.41; -0.06) and birth length (β = -0.20; 95% CI: 0.41; 0.02). Likewise, ΣDMs during 3rd trimester were near-significantly associated with decreased birth weight (β = -0.18; 95% CI: 0.37; 0.01). In turn, increased urinary TCPy during 1st trimester was associated with a decreased head circumference (β = -0.31; 95% CI: 0.57; -0.06). Finally, an increase in 3-PBA in the 1st trimester was associated with a decreased gestational age (β = -0.36 95% CI: 0.65-0.08), whereas increased 3-PBA at 1st and 3rd trimester was associated with prematurity. These results indicate that prenatal exposure to organophosphate and pyrethroid insecticides could affect normal foetal growth, shorten gestational age and alter anthropometric measures at birth.

Association of 3-Phenoxybenzoic Acid Exposure during Pregnancy with Maternal Outcomes and Newborn Anthropometric Measures: Results from the IoMum Cohort Study

The aims of this study were to characterize the exposure of pregnant women living in Portugal to 3-phenoxybenzoic acid (3-PBA) and to evaluate the association of this exposure with maternal outcomes and newborn anthropometric measures. We also aimed to compare exposure in summer with exposure in winter. Pregnant women attending ultrasound scans from April 2018 to April 2019 at a central hospital in Porto, Portugal, were invited to participate. Inclusion criteria were: gestational week between 10 and 13, confirmed fetal vitality, and a signature of informed consent. 3-PBA was measured in spot urine samples by gas chromatography with mass spectrometry (GC-MS). The median 3-PBA concentration was 0.263 (0.167; 0.458) µg/g creatinine (n = 145). 3-PBA excretion was negatively associated with maternal pre-pregnancy body mass index (BMI) (p = 0.049), and it was higher during the summer when compared to winter (p < 0.001). The frequency of fish or yogurt consumption was associated positively with 3-PBA excretion, particularly during the winter (p = 0.002 and p = 0.015, respectively), when environmental exposure is low. Moreover, 3-PBA was associated with levothyroxine use (p = 0.01), a proxy for hypothyroidism, which could be due to a putative 3-PBA-thyroid hormone antagonistic effect. 3-PBA levels were not associated with the anthropometric measures of the newborn. In conclusion, pregnant women living in Portugal are exposed to 3-PBA, particularly during summer, and this exposure may be associated with maternal clinical features.

Pesticide exposure and child growth in low- and middle-income countries: A systematic review

BACKGROUND

In low- and middle-income countries (LMICs), pesticides are widely used in agricultural and residential settings. Little is known about how pesticides affect child growth.

OBJECTIVES

To systematically review and synthesise the evidence on the associations between pesticide exposure and adverse birth outcomes and/or impaired postnatal growth in children up to 5 years of age in LMICs.

METHODS

We searched 10 databases from inception through November 2021. We included cohort and cross-sectional studies investigating associations between self-reported or measured prenatal or postnatal pesticide exposure and child growth (postnatal child linear/ponderal growth, and/or birth outcomes). Two researchers screened studies, extracted data, and assessed certainty using GRADE. The protocol was preregistered with PROSPERO (CRD42021292919).

RESULTS

Of 939 records retrieved, 31 studies met inclusion criteria (11 cohort, 20 cross-sectional). All studies assessed prenatal exposure. Twenty-four studies reported on birth weight. Four found positive associations with organochlorines (0.01-0.25 standardised mean difference (SMD)) and two found negative associations (-0.009 SMD to -55 g). Negative associations with organophosphates (-170 g, n = 1) and pyrethroids (-97 to -233 g, n = 2) were also documented. Two (out of 15) studies reporting on birth length found positive associations with organochlorines (0.21-0.25 SMD) and one found negative associations (-0.25 to -0.32 SMD). Organophosphate exposure was negatively associated with birth length (-0.37 cm, n = 1). Organophosphate exposure was also associated with higher risk/prevalence of low birth weight (2 out of nine studies) and preterm birth (2 out of six studies). Certainty of the evidence was "very low" for all outcomes.

CONCLUSION

The limited literature from LMICs shows inconclusive associations between prenatal pesticide exposure, child growth, and birth outcomes. Studies with accurate quantitative data on exposure to commonly used pesticides in LMICs using consistent methodologies in comparable populations are needed to better understand how pesticides influence child growth.

Urinary 2,4-dichlorophenoxyacetic acid in Chinese pregnant women at three trimesters: Variability, exposure characteristics, and association with oxidative stress biomarkers

Widespread exposure to herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) could have potential adverse health effects on pregnant women. However, related data are scarce. This study aimed to characterize 2,4-D exposure among three trimesters of pregnancy and to explore the relationship of 2,4-D with oxidative stress biomarkers [i.e., 8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-hydroxy guanosine (8-OHG), and 4-hydroxy nonenal mercapturic acid (HNEMA)] in urine. The present study analyzed 3675 urine samples of 1225 women (across the three trimesters of pregnancy) in Wuhan, central China. 2,4-D was detectable in 97.4% of the urine samples. The median unadjusted concentration of 2,4-D was 0.12 ng/mL, and the corresponding concentration adjusted by urinary specific gravity (SG-adjusted) was 0.13 ng/mL. The intraclass correlation coefficient of 2,4-D (SG-adjusted concentrations) was 0.07 across the three trimesters. Significantly higher urinary levels of 2,4-D were found in samples from younger pregnant women/samples collected during winter. In addition, significantly positive association between urinary concentrations of oxidative stress biomarkers and 2,4-D were found in repeated analysis; an interquartile range increase in 2,4-D was significantly (p < 0.001) associated with a 20.8% increase in 8-OHG, a 26.7% increase in 8-OHdG, and a 30.7% increase in HNEMA, respectively. Such associations were also found in trimester-specific analyses. This is the first time to quantify the urinary 2,4-D of pregnant women in China, and this study found significantly positive associations of 2,4-D with oxidative stress biomarkers. Further studies are needed to verify such associations and explore other potential adverse effects of 2,4-D exposure.

First Trimester of Pregnancy as the Sensitive Period for the Association between Prenatal Mosquito Coil Smoke Exposure and Preterm Birth

Mosquito coils are efficient mosquito repellents and mosquito coil smoke (MCS) contributes to indoor air pollution. However, no prior population-based study has investigated whether prenatal MCS exposure is a risk factor for preterm birth (PTB) and whether exposure to MCS in different trimesters of pregnancy is associated with different levels of risk. The sample involved 66,503 mother-child dyads. Logistic regression models were used to examine the relationships between prenatal MCS exposure during different trimesters of pregnancy and PTB. We found that prenatal MCS exposure was associated with a greater likelihood of PTB (OR = 1.12, 95%CI: 1.05-1.20). The prenatal MCS exposure during the first trimester was associated with 1.17 (95%CI: 1.09-1.25) times the odds of being PTB, which was higher than exposure during the second trimester (OR = 1.11, 95%CI: 1.03-1.19) and during the third trimester (OR = 1.08, 95%CI: 1.01-1.16). In the stratified analysis, prenatal MCS exposure significantly increased PTB risk among girls but not among boys. Our results indicated that maternal MCS exposure during pregnancy was associated with PTB and that the first trimester might be the sensitive period. In light of these findings, public health interventions are needed to reduce prenatal exposure to MCS, particularly during the first trimester of pregnancy.

Association of urinary metabolites of non-persistent pesticides with serum sex hormones among the US females: NHANES 2013-2014

BACKGROUND

Evidence indicated the possibility of non-persistent pesticides disrupting the homeostasis of sex hormones. However, few studies have focused on this relationship in females. We aimed to explore the relationship between non-persistent pesticide exposure and sex hormones among the US females from the National Health and Nutrition Examination Survey 2013-2014.

METHODS

A total of 790 females, including girls (6-11 years), female adolescents (12-19 years), and adult females (>19 years), were enrolled in this study. Age stratified associations of individual non-persistent pesticide metabolites and their mixtures with sex hormones were analyzed by weighted multiple linear regression and Bayesian kernel machine regression (BKMR) using spot urinary non-persistent pesticide measurement, including 2,4-dichlorophenoxyacetic acid (2,4-D), 3,5,6-trichloropyridinol (TCPY), para-nitrophenol (PNP) and 3-phenoxybenzoic acid (3-PBA), and three serum sex hormones [total testosterone (TT), estradiol (E2) and sex hormone binding globulin (SHBG)].

RESULTS

In girls, weighted multivariate linear regression indicated that both 2,4-D and PNP were negatively associated with TT, and TCPY was inversely associated with SHBG. In female adolescents, TCPY was negatively associated with TT and E2, and 3-PBA was negatively associated with SHBG; positive associations were detected both in 2,4-D with SHBG, and in PNP with TT. In adult females, a higher concentration of 3-PBA was associated with higher levels of TT. The BKMR model showed that in female adolescents, the concentrations of pesticide metabolite mixtures at or above the 55th percentile were negatively related to the levels of E2 compared with their mixtures at 50th percentile, and an inverse U-shaped exposure-response function between PNP and E2 was found.

CONCLUSIONS

Associations between the four non-persistent pesticide metabolites and serum sex hormones were identified in the US females from NHANES 2013-2014 and these associations were age dependent, especially in adolescents. Large-scale cohort studies are needed to confirm these findings and elucidate the potential biological mechanisms.

Urinary organophosphate metabolite concentrations and birth sizes among women conceiving through in vitro fertilization in Shanghai, China

BACKGROUND

Few studies have examined the adverse birth sizes of preconception exposure to organophosphate pesticides (OPs) in women undergoing in vitro fertilization (IVF).

OBJECTIVES

We investigated the relationship of preconception OP exposure with birth sizes among Chinese women undergoing IVF.

METHODS

This study included 302 couples seeking infertility treatment in the China National Birth Cohort Study, from Shanghai, China, who gave birth to singleton infants between 2018 and 2021. Clinical data were collected from medical records. We measured the concentrations of six nonspecific dialkyl phosphates (DAP) metabolites of OPs [diethylthiophosphate (DETP), diethylphosphate (DEP), diethyldithiophosphate (DEDTP), dimethyldithiophosphate (DMTP), dimethylphosphate (DMP), and dimethyldithiophosphate (DMDTP)] in maternal urine. DMDTP and DEDTP were precluded from further analyses due to the low detection rates. Generalized linear models (GLMs) and weighted quantile sum (WQS) regression analyses were performed to examine the individual and joint effects of OP exposures on gestational age, birth weight, body length, and ponderal index. Odder ratio (OR) of preterm birth were estimated using logistic regression models.

RESULTS

Women in the highest as compared with lowest quartile of DEP had shorter gestational age (β = - 0.68; 95% CI = -1.24, -0.11). The association was modified by sex, with boys showing larger decreases in gestational age (β = - 0.86; 95% CI = -1.60, -0.13). No associations were found between other DAP metabolites and birth sizes. Results from linear models with individual DAP metabolites were corroborated by the WQS regression where DEP had the largest contribution to the overall mixture effect on gestational age (weight = 0.70). Moreover, DEP concentration was associated with an elevated risk of preterm birth (OR = 1.35, 95% CI = 1.11, 2.25).

CONCLUSION

Preconception DEP concentration was associated with shortened gestational age and increased risk of preterm birth, and the association was more pronounced among boys than girls.

Combining Urinary Biomarker Data From Studies With Different Measures of Urinary Dilution

BACKGROUND

Guidance is lacking for how to combine urinary biomarker data across studies that use different measures of urinary dilution, that is, creatinine or specific gravity.

METHODS

Among 741 pregnant participants from four sites of The Infant Development and Environment Study (TIDES) cohort, we assessed the relation of maternal urinary di-2-ethylhexyl phthalate (DEHP) concentrations with preterm birth. We compared scenarios in which all sites measured either urinary creatinine or specific gravity, or where measure of dilution differed by site. In addition to a scenario with no dilution adjustment, we applied and compared three dilution-adjustment approaches: a standard regression-based approach for creatinine, a standard approach for specific gravity (Boeniger method), and a more recently developed approach that has been applied to both (covariate-adjusted standardization method). For each scenario and dilution-adjustment method, we estimated the association between a doubling in the molar sum of DEHP (∑DEHP) and odds of preterm birth using logistic regression.

RESULTS

All dilution-adjustment approaches yielded comparable associations (odds ratio [OR]) that were larger in magnitude than when we did not perform dilution adjustment. A doubling of ∑DEHP was associated with 9% greater odds of preterm birth (OR = 1.09, 95% confidence interval [CI] = 0.91, 1.30) when applying no dilution-adjustment method, whereas dilution-adjusted point estimates were higher, and similar across all scenarios and methods: 1.13-1.20 (regression-based), 1.15-1.18 (Boeniger), and 1.14-1.21 (covariate-adjusted standardization).

CONCLUSIONS

In our applied example, we demonstrate that it is possible and straightforward to combine urinary biomarker data across studies when measures of dilution differ.

Exposure to non-persistent pesticides in the Spanish population using biomonitoring: A review

Although Spain does not have a regular national human biomonitoring program yet, different research groups are active in evaluating the exposure of children and adults to chemicals. In the last seven years, several studies in Spain have evaluated the internal exposure of the population to currently used pesticides. The present review analyzes the scope of these studies, the employed analytical methods and the main results of the exposure and risk, mainly for children and mothers. The frequency of exposure to biomarkers of exposure to organophosphate pesticides is high. Some non-specific dialkyl phosphate metabolites (DAPs), such as the diethyl phosphate (DEP), present Detection Frequencies (DFs) in the range of 65-92% in various studies. Also, the specific biomarker of the chlorpyrifos (3,5,6-trichloro-2-pyridinol, TCPy), achieves Detection Frequencies between 74% and 100% in many studies. For pyrethroids, the metabolite 3-phenoxybenzoic acid (PBA) is present, in general, in more than the 65% of the studied samples. Highly polar herbicides were only assessed in one study and both glyphosate and its metabolite aminomethylphosphonic acid showed Detection Frequencies around 60%. However, putting the biomonitoring data in a risk assessment context, the mean Hazard Quotient (HQ), used as a metric for the individual risk, ranges from 0.0006 (glyphosate) to 0.93 in farm workers (parathion), which means that is unlike that the exposure poses a health concern (HQ < 1).