Prenatal Exposure to Polybrominated Flame Retardants and Fetal Growth in the INMA Cohort (Spain)

Abstract

Our aim was to investigate the relation between PBDEs and fetal growth or newborn anthropometry in a Spanish cohort (2003-2008). PBDE congeners (BDE-47, -99, -153, -154, and -209) were determined in serum of 670 mothers at gestational week 12 and in 534 umbilical cord samples. Abdominal circumference (AC), estimated fetal weight (EFW), femur length (FL), and biparietal diameter (BPD) during gestation were measured by ultrasounds. At birth, weight (BW), head circumference (HC), and length (BL) were also measured. We assessed growth in the intervals between 12-20 and 20-34 weeks of gestation and size at birth by standard deviation (SD)-scores adjusted for constitutional characteristics. We conducted multivariate linear regression analyses between PBDE congeners and their sum (ΣPBDEs) and outcomes. We found statistically significant inverse associations between ΣPBDEs and AC, EFW, and BPD at weeks 20-34 and HC at birth. Regarding congeners, the association was clearer with BDE-99, with inverse associations being found with AC, EFW, and BPD at weeks 20-34, and with BW and HC at delivery. These outcomes decreased between 1.3% and 3.5% for each 2-fold PBDE increase. Concerning matrices, we found statistically significant inverse associations with BPD, HC, and BW when using maternal serum, and for AC and EFW with cord serum. In conclusion, PBDEs may impair fetal growth in late pregnancy and reduce birth size.

Figure 1

Association between prenatal PBDE concentrations and fetal growth measurements or newborn size: The INMA Cohort, 2003–2008 (Spain). Percent change in fetal (shaded white) or newborn (shaded gray) measurements associated with a 2-fold increase in PBDE concentrations. ⁺p-value <0.1; * p-value <0.05; ** p-value <0.01. AC: abdominal circumference; BL: birth length; BPD: biparietal diameter; BW: birth weight; EFW: estimated fetal weight; FL: femur length; HC: head circumference; PBDE: polybrominated diphenyl ether; ∑: sum.

Figure 2

Sensitivity analysis of the association between prenatal concentrations of ∑PBDEs and fetal growth measurements or newborn size: The INMA Cohort, 2003–2008 (Spain). Percent change in fetal (shaded white) or newborn (shaded gray) measurements associated with a 2-fold increase in ∑PBDE concentrations. AC: abdominal circumference; BL: birth length; BW: birth weight; BPD: biparietal diameter; EFW: estimated fetal weight; HC: head circumference; HCB: hexachlorobenzene; FL: femur length; ∑PCBs: sum of PCB 138, 153, and 180; ∑PBDEs: sum of polybrominated diphenyl ethers. Main analysis: results from multiple imputation. Complete case: excluded cases with missing values in covariates and fixed imputation of values