-
Overall, 202 maternal-infant pairs (101 FGR cases and 101 controls) were enrolled in the present study. The population characteristics of FGR cases and healthy newborns were listed and compared (Table 1). The average birth weight and gestational age of FGR cases were (2.29 ± 0.43) kg and (36.4 ± 4.0) weeks, respectively, which were significantly lower than those of the controls (3.31 ± 0.34) kg and (39.1 ± 1.1) weeks, respectively, P < 0.001). The Quetelet index of FGR cases was significantly lower than that of controls [(48.31 ± 7.56) vs. (66.03 ± 6.41), P < 0.001]. In terms of maternal feature, no significant difference was observed in the maternal age, delivery mode, monthly income, and pregnancy syndrome between the FGR cases and healthy controls. Regarding placental growth indicators, differences were detected in the placental length (17.03 vs. 18.37, P < 0.001), breadth (16.68 vs. 18.54, P < 0.001), and surface area (224.21 vs. 270.38, P < 0.001) between the FGR cases and controls.
Table 1. Demographic characteristic of maternal-newborn pairs
Demographic characteristic Total (n = 202) FGR (n = 101) Control (n = 101) P-value Gestational age (weeks) 37.8 ± 3.2 36.4 ± 4.0 39.1 ± 1.1 < 0.001* Newborn’s birth weight (kg) 2.81 ± 0.64 2.29 ± 0.43 3.31 ± 0.34 < 0.001* Newborn’s birth length (cm) 48.83 ± 3.79 47.47 ± 5.09 50.09 ± 0.69 < 0.001* Quetelet index 57.49 ± 11.29 48.31 ± 7.56 66.03 ± 6.41 < 0.001* Maternal age (years) 27.8 ± 4.3 27.1 ± 4.9 28.3 ± 3.7 0.097 Placental indicator Length (cm) 17.85 ± 2.26 17.03 ± 1.97 18.37 ± 2.29 < 0.001* Breadth (cm) 17.82 ± 2.25 16.68 ± 2.15 18.54 ± 2.00 < 0.001* Surface area (cm2) 252.39 ± 59.54 224.21 ± 47.32 270.38 ± 59.77 < 0.001* Neonate’s sex 0.778 Male 96 49 47 Female 106 52 54 Delivery mode 0.198 Vaginal delivery 93 71 22 Cesarean delivery 109 79 30 Maternal education level 0.011* Below high school 48 27 21 High school 88 51 37 College and above 66 23 43 Monthly income (Yuan) 0.665 < 5,000 79 38 41 > 5,000 123 63 60 Pregnancy syndrome 0.150 No 149 70 79 Yes 53 31 22 Note. *P-value < 0.05 is statistically significant. -
Table 2 shows the median (interquartile range) concentrations of PBDE congeners in maternal serum between the FGR and control groups. The detection rate of seven PBDE homologues were more than 50% (BDE-17, -47, -66, -153, -207, -208, and -209). The concentration of BDE-209 was the highest in the maternal serum of FGR cases and controls. The maternal serum PBDE concentrations of FGR group, especially BDE-207, -208, -209, and ∑19PBDEs, were significantly higher than those of healthy controls.
Table 2. PBDE level in maternal serum between FGR cases and controls (ng/g)
PBDE congener Detection rate (%) FGR Control P-value Median (P25, P75) Median (P25, P75) BDE-17 64.4 0.644 (0.154, 1.594) 0.436 (0.090, 1.040) 0.140 BDE-28&33 40.0 0.175 (< LOD, 1.962) 0.313 (< LOD, 1.498) 0.934 BDE-47 56.9 0.524 (< LOD, 1.645) 0.455 (<LOD, 1.255) 0.279 BDE-49 26.7 < LOD (< LOD, 0.322) < LOD (< LOD, 1.286) 0.022* BDE-66 63.9 0.540 (0.158, 3.751) 0.526 (< LOD, 1.793) 0.160 BDE-99 24.8 < LOD (< LOD, 0.205) < LOD (< LOD, 0.435) 0.929 BDE-100 29.2 < LOD (< LOD, 0.298) < LOD (< LOD, 0.320) 0.812 BDE-138 39.1 < LOD (< LOD, 1.839) 0.221 (< LOD, 1.941) 0.371 BDE-153 65.3 2.531 (0.703, 5.348) 1.825 (0.412, 3.122) 0.059 BDE-154 31.2 < LOD (< LOD, 0.391) < LOD (< LOD, 0.724) 0.856 BDE-183 6.9 < LOD (< LOD, < LOD) < LOD (< LOD, < LOD) 0.040* BDE-190 8.9 < LOD (< LOD, < LOD) < LOD (< LOD, <LOD) 0.366 BDE-196 24.3 < LOD (< LOD, 0.704) < LOD (< LOD, 0.862) 0.984 BDE-203 20.3 < LOD (< LOD, 0.439) < LOD (< LOD, < LOD) 0.690 BDE-206 46.0 1.709 (< LOD, 9.007) < LOD (< LOD, 3.379) 0.035* BDE-207 52.0 2.598 (< LOD, 8.449) 0.698 (< LOD, 3.058) 0.002* BDE-208 55.0 1.562 (0.298, 5.259) 1.041 (< LOD, 2.679) 0.012* BDE-209 57.4 7.867 (< LOD, 46.264) 5.908 (< LOD, 18.732) 0.045* ∑19PBDEs 83.7 31.948 (14.119, 93.455) 22.630 (9.204, 43.939) 0.009* Note. LOD: limit of detection.*P-value < 0.05 is statistically significant. -
Table 3 shows the associations between maternal serum PBDE levels and placental size. A unit increase in BDE-17, -153, -207, -209, and ∑19PBDE concentrations in maternal serum was related to a decrease of 0.19–0.23 cm in placental length. Every unit increase in BDE-17, -153, -207, -208, -209, and ∑19PBDE concentrations was associated with 0.18–0.31 cm decrease in placental breadth. Similarly, concentrations of BDE-17, -153, -207, -208, -209, and ∑19PBDEs were significantly negatively correlated with the placental surface.
Table 3. Correlation between PBDE concentrations and placental indicator
PBDE congener Length Breadth Surface area Beta P-value Beta P-value Beta P-value BDE-17 −0.234 0.004* −0.184 0.024* −0.224 0.006* BDE-47 −0.122 0.135 −0.079 0.335 −0.107 0.191 BDE-66 −0.031 0.705 −0.069 0.397 −0.041 0.618 BDE-153 −0.233 0.004* −0.314 < 0.001* −0.283 < 0.001* BDE-207 −0.190 0.019* −0.211 0.009* −0.204 0.012* BDE-208 −0.104 0.201 −0.220 0.007* −0.173 0.034* BDE-209 −0.209 0.010* −0.270 0.001* −0.252 0.002* ∑19PBDEs −0.228 0.005* −0.296 < 0.001* −0.274 0.001* Note. * P-value < 0.05 is statistically significant. -
Table 4 shows the relationships between maternal serum PBDE levels and birth outcome indicators, including birth weight, birth length, gestational age, and Quetelet index. A unit increase in BDE-47, -66, -153, -207, -208, -209, and ∑19PBDE concentrations was related to a decrease of 0.160.27 g in birth weight. Every unit increase in BDE-207, -208, -209, and ∑19PBDE concentrations were associated with 0.18, 0.21, 0.18, and 0.20 cm decreases in birth length, respectively. Meanwhile, gestational age significantly decreased with the increase in BDE-207, -208, -209, and ∑19PBDEs. Likewise, concentrations of BDE-47, -66, -153, -207, -208, -209, and ∑19PBDEs showed a significantly negative association with Quetelet index.
Table 4. Correlation between PBDE concentrations and birth outcome indicator
PBDE congener Birth weight Birth length Gestational age Quetelet index Beta P-value Beta P-value Beta P-value Beta P-value BDE-17 −0.127 0.099 −0.041 0.599 −0.054 0.483 −0.126 0.106 BDE-47 −0.162 0.036* −0.058 0.461 −0.122 0.113 −0.173 0.026* BDE-66 −0.228 0.003* −0.102 0.189 −0.086 0.266 −0.228 0.003* BDE-153 −0.183 0.017* −0.139 0.075 −0.105 0.174 −0.180 0.020* BDE-207 −0.268 < 0.001* −0.184 0.018* −0.198 0.010* −0.242 0.002* BDE-208 −0.253 0.001* −0.213 0.006* −0.280 < 0.001* −0.204 0.008* BDE-209 −0.255 0.001* −0.176 0.023* −0.247 0.001* −0.258 0.001* ∑19PBDEs −0.284 < 0.001* −0.201 0.010* −0.261 0.001* −0.277 < 0.001* Note. * P-value < 0.05 is statistically significant. -
The effect of each BDE congener on FGR birth was assessed after adjusting for potential confounders, including gestational age, education, monthly income, and pregnancy syndrome. As shown in Table 5, BDE-66 [odds ratio (OR) = 1.17; 95% confidence interval (CI): 1.04 to 1.32], BDE-153 (OR = 1.12; 95% CI: 1.01 to 1.23), BDE-207 (OR = 1.11; 95% CI: 1.04 to 1.19), BDE-208 (OR = 1.11; 95% CI: 1.03 to 1.20), BDE-209 (OR = 1.02; 95% CI: 1.01 to 1.03), and ∑19PBDEs (OR = 1.11; 95% CI: 1.00 to 1.02) concentrations in maternal serum were significantly associated with the increased risk of FGR. After adjusting for confounders, the association of BDE-207 (OR = 1.10; 95% CI: 1.02 to 1.19) and ∑19PBDE (OR = 1.01; 95% CI: 1.00 to 1.02) concentrations with FGR birth remained statistically significant.
Table 5. Effects of PBDEs in maternal serum on FGR risk
PBDE congener Unadjusted Adjusteda OR ( 95% CI) P-value OR ( 95% CI) P-value BDE-17 1.23 (0.92, 1.63) 0.157 1.21 (0.87, 1.67) 0.254 BDE-47 1.16 (0.99, 1.36) 0.058 1.13 (0.92, 1.38) 0.249 BDE-66 1.17 (1.04, 1.32) 0.010* 1.16 (0.98, 1.39) 0.087 BDE-153 1.12 (1.01, 1.23) 0.027* 1.12 (0.98, 1.27) 0.089 BDE-207 1.11 (1.04, 1.19) 0.001* 1.10 (1.02, 1.19) 0.016* BDE-208 1.11 (1.03, 1.20) 0.006* 1.10 (0.98, 1.23) 0.125 BDE-209 1.02 (1.01, 1.03) 0.003* 1.01 (0.99, 1.03) 0.092 ∑19PBDEs 1.01 (1.00, 1.02) 0.001* 1.01 (1.00, 1.02) 0.037* Note. *P-value < 0.05 is statistically significant;
aAdjusting for gestational age, education, income, and pregnancy syndrome.
doi: 10.3967/bes2020.112
Concentrations of Polybrominated Diphenyl Ethers in Maternal Blood, Placental Size, and Risk for Fetal Growth Restriction: A Nested Case-control Study
-
Abstract:
Objective To explore the effects of prenatal exposure to polybrominated diphenyl ethers (PBDEs) on placental size and birth outcomes. Methods Based on the perspective Wenzhou Birth Cohort, this nested case-control study included 101 fetal growth restriction (FGR) and 101 healthy newborns. Maternal serum samples were collected during the third trimester and measured for PBDEs by gas chromatography tandem mass spectrometry. The basic information of mother-newborn pairs was collected from questionnaires, whereas the placental size and birth outcomes of newborns were obtained from hospital records. Results A total of 19 brominated diphenyle ether (BDE) congeners were detected in maternal serum samples. Higher concentrations of BDE-207, -208, -209, and ∑19PBDEs were detected in FGR cases than in controls. Increased BDE-207, -208, -209, and ∑19PBDEs levels in maternal serum were related to decreased placental length, breadth, surface area, birth weight, birth length, gestational age, and Quetelet index of newborns. After adjusting for confounders, BDE-207 and ∑19PBDE concentrations in maternal serum were significantly associated with an increased risk of FGR. Conclusion A negative association was found between PBDE levels in maternal serum and placental size and birth outcomes. Prenatal PBDE exposure may be associated with elevated risk of the incidence of FGR birth. -
Table 1. Demographic characteristic of maternal-newborn pairs
Demographic characteristic Total (n = 202) FGR (n = 101) Control (n = 101) P-value Gestational age (weeks) 37.8 ± 3.2 36.4 ± 4.0 39.1 ± 1.1 < 0.001* Newborn’s birth weight (kg) 2.81 ± 0.64 2.29 ± 0.43 3.31 ± 0.34 < 0.001* Newborn’s birth length (cm) 48.83 ± 3.79 47.47 ± 5.09 50.09 ± 0.69 < 0.001* Quetelet index 57.49 ± 11.29 48.31 ± 7.56 66.03 ± 6.41 < 0.001* Maternal age (years) 27.8 ± 4.3 27.1 ± 4.9 28.3 ± 3.7 0.097 Placental indicator Length (cm) 17.85 ± 2.26 17.03 ± 1.97 18.37 ± 2.29 < 0.001* Breadth (cm) 17.82 ± 2.25 16.68 ± 2.15 18.54 ± 2.00 < 0.001* Surface area (cm2) 252.39 ± 59.54 224.21 ± 47.32 270.38 ± 59.77 < 0.001* Neonate’s sex 0.778 Male 96 49 47 Female 106 52 54 Delivery mode 0.198 Vaginal delivery 93 71 22 Cesarean delivery 109 79 30 Maternal education level 0.011* Below high school 48 27 21 High school 88 51 37 College and above 66 23 43 Monthly income (Yuan) 0.665 < 5,000 79 38 41 > 5,000 123 63 60 Pregnancy syndrome 0.150 No 149 70 79 Yes 53 31 22 Note. *P-value < 0.05 is statistically significant. Table 2. PBDE level in maternal serum between FGR cases and controls (ng/g)
PBDE congener Detection rate (%) FGR Control P-value Median (P25, P75) Median (P25, P75) BDE-17 64.4 0.644 (0.154, 1.594) 0.436 (0.090, 1.040) 0.140 BDE-28&33 40.0 0.175 (< LOD, 1.962) 0.313 (< LOD, 1.498) 0.934 BDE-47 56.9 0.524 (< LOD, 1.645) 0.455 (<LOD, 1.255) 0.279 BDE-49 26.7 < LOD (< LOD, 0.322) < LOD (< LOD, 1.286) 0.022* BDE-66 63.9 0.540 (0.158, 3.751) 0.526 (< LOD, 1.793) 0.160 BDE-99 24.8 < LOD (< LOD, 0.205) < LOD (< LOD, 0.435) 0.929 BDE-100 29.2 < LOD (< LOD, 0.298) < LOD (< LOD, 0.320) 0.812 BDE-138 39.1 < LOD (< LOD, 1.839) 0.221 (< LOD, 1.941) 0.371 BDE-153 65.3 2.531 (0.703, 5.348) 1.825 (0.412, 3.122) 0.059 BDE-154 31.2 < LOD (< LOD, 0.391) < LOD (< LOD, 0.724) 0.856 BDE-183 6.9 < LOD (< LOD, < LOD) < LOD (< LOD, < LOD) 0.040* BDE-190 8.9 < LOD (< LOD, < LOD) < LOD (< LOD, <LOD) 0.366 BDE-196 24.3 < LOD (< LOD, 0.704) < LOD (< LOD, 0.862) 0.984 BDE-203 20.3 < LOD (< LOD, 0.439) < LOD (< LOD, < LOD) 0.690 BDE-206 46.0 1.709 (< LOD, 9.007) < LOD (< LOD, 3.379) 0.035* BDE-207 52.0 2.598 (< LOD, 8.449) 0.698 (< LOD, 3.058) 0.002* BDE-208 55.0 1.562 (0.298, 5.259) 1.041 (< LOD, 2.679) 0.012* BDE-209 57.4 7.867 (< LOD, 46.264) 5.908 (< LOD, 18.732) 0.045* ∑19PBDEs 83.7 31.948 (14.119, 93.455) 22.630 (9.204, 43.939) 0.009* Note. LOD: limit of detection.*P-value < 0.05 is statistically significant. Table 3. Correlation between PBDE concentrations and placental indicator
PBDE congener Length Breadth Surface area Beta P-value Beta P-value Beta P-value BDE-17 −0.234 0.004* −0.184 0.024* −0.224 0.006* BDE-47 −0.122 0.135 −0.079 0.335 −0.107 0.191 BDE-66 −0.031 0.705 −0.069 0.397 −0.041 0.618 BDE-153 −0.233 0.004* −0.314 < 0.001* −0.283 < 0.001* BDE-207 −0.190 0.019* −0.211 0.009* −0.204 0.012* BDE-208 −0.104 0.201 −0.220 0.007* −0.173 0.034* BDE-209 −0.209 0.010* −0.270 0.001* −0.252 0.002* ∑19PBDEs −0.228 0.005* −0.296 < 0.001* −0.274 0.001* Note. * P-value < 0.05 is statistically significant. Table 4. Correlation between PBDE concentrations and birth outcome indicator
PBDE congener Birth weight Birth length Gestational age Quetelet index Beta P-value Beta P-value Beta P-value Beta P-value BDE-17 −0.127 0.099 −0.041 0.599 −0.054 0.483 −0.126 0.106 BDE-47 −0.162 0.036* −0.058 0.461 −0.122 0.113 −0.173 0.026* BDE-66 −0.228 0.003* −0.102 0.189 −0.086 0.266 −0.228 0.003* BDE-153 −0.183 0.017* −0.139 0.075 −0.105 0.174 −0.180 0.020* BDE-207 −0.268 < 0.001* −0.184 0.018* −0.198 0.010* −0.242 0.002* BDE-208 −0.253 0.001* −0.213 0.006* −0.280 < 0.001* −0.204 0.008* BDE-209 −0.255 0.001* −0.176 0.023* −0.247 0.001* −0.258 0.001* ∑19PBDEs −0.284 < 0.001* −0.201 0.010* −0.261 0.001* −0.277 < 0.001* Note. * P-value < 0.05 is statistically significant. Table 5. Effects of PBDEs in maternal serum on FGR risk
PBDE congener Unadjusted Adjusteda OR ( 95% CI) P-value OR ( 95% CI) P-value BDE-17 1.23 (0.92, 1.63) 0.157 1.21 (0.87, 1.67) 0.254 BDE-47 1.16 (0.99, 1.36) 0.058 1.13 (0.92, 1.38) 0.249 BDE-66 1.17 (1.04, 1.32) 0.010* 1.16 (0.98, 1.39) 0.087 BDE-153 1.12 (1.01, 1.23) 0.027* 1.12 (0.98, 1.27) 0.089 BDE-207 1.11 (1.04, 1.19) 0.001* 1.10 (1.02, 1.19) 0.016* BDE-208 1.11 (1.03, 1.20) 0.006* 1.10 (0.98, 1.23) 0.125 BDE-209 1.02 (1.01, 1.03) 0.003* 1.01 (0.99, 1.03) 0.092 ∑19PBDEs 1.01 (1.00, 1.02) 0.001* 1.01 (1.00, 1.02) 0.037* Note. *P-value < 0.05 is statistically significant;
aAdjusting for gestational age, education, income, and pregnancy syndrome. -
[1] de Wit CA. An overview of brominated flame retardants in the environment. Chemosphere, 2002; 46, 583−624. doi: 10.1016/S0045-6535(01)00225-9 [2] Abbasi G, Li L, Breivik K. Global historical stocks and emissions of PBDEs. Environ Sci Technol, 2019; 53, 6330−40. doi: 10.1021/acs.est.8b07032 [3] Genuis SK, Birkholz D, Genuis SJ. Human excretion of polybrominated diphenyl ether flame retardants: blood, urine, and sweat study. Bio Med Res Int, 2017; 2017, 3676089. [4] Jiang H, Lin ZK, Wu YY, et al. Daily intake of polybrominated diphenyl ethers via dust and diet from an e-waste recycling area in China. J Hazard Mater, 2014; 276, 35−42. doi: 10.1016/j.jhazmat.2014.05.014 [5] Ni K, Lu YL, Wang TY, et al. A review of human exposure to polybrominated diphenyl ethers (PBDEs) in China. Int J Hyg Environ Health, 2013; 216, 607−23. doi: 10.1016/j.ijheh.2013.02.002 [6] Sharma D, Farahbakhsh N, Shastri S, et al. Intrauterine growth restriction-part 2. J Matern-Fetal Neonatal Med, 2016; 29, 4037−48. doi: 10.3109/14767058.2016.1154525 [7] Kesavan K, Devaskar SU. Intrauterine growth restriction: postnatal monitoring and outcomes. Pediatr Clin North Am, 2019; 66, 403−23. doi: 10.1016/j.pcl.2018.12.009 [8] Nardozza LMM, Caetano ACR, Zamarian ACP, et al. Fetal growth restriction: current knowledge. Arch Gynecol Obstet, 2017; 295, 1061−77. doi: 10.1007/s00404-017-4341-9 [9] Gómara B, Herrero L, Ramos JJ, et al. Distribution of polybrominated diphenyl ethers in human umbilical cord serum, paternal serum, maternal serum, placentas, and breast milk from Madrid population, Spain. Environ Sci Technol, 2007; 41, 6961−8. doi: 10.1021/es0714484 [10] Leonetti C, Butt CM, Hoffman K, et al. Brominated flame retardants in placental tissues: associations with infant sex and thyroid hormone endpoints. Environ Health, 2016; 15, 113. doi: 10.1186/s12940-016-0199-8 [11] Zhao Y, Song Q, Cao ZJ, et al. Umbilical cord blood PBDEs concentrations in relation to placental size at birth. Chemosphere, 2018; 201, 20−4. doi: 10.1016/j.chemosphere.2018.02.121 [12] van Abeelen AFM, de Rooij SR, Osmond C, et al. The sex-specific effects of famine on the association between placental size and later hypertension. Placenta, 2011; 32, 694−8. doi: 10.1016/j.placenta.2011.06.012 [13] Hornung RW, Reed LD. Estimation of average concentration in the presence of nondetectable values. Appl Occup Environ Hyg, 1990; 5, 46−51. doi: 10.1080/1047322X.1990.10389587 [14] McMaster-Fay RA. Failure of physiologic transformation of the spiral arteries of the uteroplacental circulation in patients with preterm labor and intact membranes. Am J Obstet Gynecol, 2004; 191, 1837−8. [15] Sheppard BL, Bonnar J. An ultrastructural study of utero-placental spiral arteries in hypertensive and normotensive pregnancy and fetal growth retardation. Br J Obstet Gynaecol, 1981; 88, 695−705. doi: 10.1111/j.1471-0528.1981.tb01268.x [16] Tong Z, Zhang XW, Chen BM, et al. The effect of subclinical maternal thyroid dysfunction and autoimmunity on intrauterine growth restriction: a systematic review and meta-analysis. Medicine, 2016; 95, e3677. doi: 10.1097/MD.0000000000003677 [17] Mazdai A, Dodder NG, Abernathy MP, et al. Polybrominated diphenyl ethers in maternal and fetal blood samples. Environ Health Perspect, 2003; 111, 1249−52. doi: 10.1289/ehp.6146 [18] Choi G, Kim S, Kim S, et al. Occurrences of major polybrominated diphenyl ethers (PBDEs) in maternal and fetal cord blood sera in Korea. Sci Total Environ, 2014; 491-2, 219−26. doi: 10.1016/j.scitotenv.2014.02.071 [19] Shin MY, Lee S, Kim HJ, et al. Polybrominated diphenyl ethers in maternal serum, breast milk, umbilical cord serum, and house dust in a South Korean birth panel of mother-neonate pairs. Int J Environ Res Public Health, 2016; 13, 767. doi: 10.3390/ijerph13080767 [20] Boon JP, Lewis WE, Tjoen-A-Choy MR, et al. Levels of polybrominated diphenyl ether (PBDE) flame retardants in animals representing different trophic levels of the North Sea food Web. Environ Sci Technol, 2002; 36, 4025−32. doi: 10.1021/es0158298 [21] Thuresson K, Bergman Å, Jakobsson K. Occupational exposure to commercial decabromodiphenyl ether in workers manufacturing or handling flame-retarded rubber. Environ Sci Technol, 2005; 39, 1980−6. doi: 10.1021/es048511z [22] Darnerud PO, Lignell S, Aune M, et al. Time trends of polybrominated diphenylether (PBDE) congeners in serum of Swedish mothers and comparisons to breast milk data. Environ Res, 2015; 138, 352−60. doi: 10.1016/j.envres.2015.02.031 [23] Miranda ML, Anthopolos R, Wolkin A, et al. Associations of birth outcomes with maternal polybrominated diphenyl ethers and thyroid hormones during pregnancy. Environ Int, 2015; 85, 244−53. doi: 10.1016/j.envint.2015.09.015 [24] Vizcaino E, Grimalt JO, Fernández-Somoano A, et al. Transport of persistent organic pollutants across the human placenta. Environ Int, 2014; 65, 107−15. doi: 10.1016/j.envint.2014.01.004 [25] Park HR, Kamau PW, Loch-Caruso R. Involvement of reactive oxygen species in brominated diphenyl ether-47-induced inflammatory cytokine release from human extravillous trophoblasts in vitro. Toxicol Appl Pharmacol, 2014; 274, 283−92. doi: 10.1016/j.taap.2013.11.015 [26] Park HR, Loch-Caruso R. Protective effect of (±)α-tocopherol on brominated diphenyl ether-47-stimulated prostaglandin pathways in human extravillous trophoblasts in vitro. Toxicol in Vitro, 2015; 29, 1309−18. doi: 10.1016/j.tiv.2015.05.015 [27] Manuguerra S, Espinosa Ruiz C, Santulli A, et al. Sub-lethal doses of polybrominated diphenyl ethers, in vitro, promote oxidative stress and modulate molecular markers related to cell cycle, antioxidant balance and cellular energy management. Int J Environ Res Public Health, 2019; 16, 588. doi: 10.3390/ijerph16040588 [28] Zhao XM, Peng SQ, Xiang Y, et al. Correlation between prenatal exposure to polybrominated diphenyl ethers (PBDEs) and infant birth outcomes: a meta-analysis and an experimental study. Int J Environ Res Public Health, 2017; 14, 268. doi: 10.3390/ijerph14030268 [29] Lopez-Espinosa MJ, Costa O, Vizcaino E, et al. Prenatal exposure to polybrominated flame retardants and fetal growth in the INMA Cohort (Spain). Environ Sci Technol, 2015; 49, 10108−16. doi: 10.1021/acs.est.5b01793 [30] Zhao Y, Liu PC, Wang JY, et al. Umbilical cord blood PBDEs concentrations are associated with placental DNA methylation. Environ Int, 2016; 97, 1−6. doi: 10.1016/j.envint.2016.10.014 [31] Kim S, Cho YH, Lee I, et al. Prenatal exposure to persistent organic pollutants and methylation of LINE-1 and imprinted genes in placenta: A CHECK cohort study. Environ Int, 2018; 119, 398−406. doi: 10.1016/j.envint.2018.06.039