Prenatal urinary BTEX metabolite levels and length of gestation: preliminary results from a metropolitan Detroit birth cohort.

While the common volatile organic compound mixture benzene, toluene, ethylbenzene and xylene (BTEX) is associated with preterm birth (PTB), most evidence derives from estimated rather than direct measures of exposure. Metabolites of BTEX were measured in urine samples from pregnant participants (N=40) to conduct a preliminary association study of BTEX metabolites and length of gestation. Metabolites of ethylbenzene (phenylglyoxylic acid (PGA)) and xylene (methylhippuric acid (MHA)) were negatively correlated with gestational length; the Spearman correlation coefficient (ρ) for PGA and gestational length was ρ=-0.37 (p=0.018) and for MHA and gestational length was ρ=-0.35 (p=0.026). Preliminary findings suggest prenatal ethylbenzene and xylene exposure may be associated with shorter gestational length. Ongoing work in a larger sample is underway to examine associations between BTEX metabolites, measured longitudinally across pregnancy, and PTB.