Quantitation of phosphatidylethanols in dried blood spots to determine rates of prenatal alcohol exposure in Ontario.

BACKGROUND Understanding rates of prenatal alcohol exposure (PAE) in a population is necessary to ensure that proper medical and social supports and interventions are in place. This study sought to estimate PAE in Ontario by quantifying phosphatidylethanol (PEth) homologues in over 2000 residual neonatal dried blood spots (DBS). METHODS A random selection of 2011 residual DBS collected over a one-week time period were anonymized and extracted. A targeted liquid chromatography-mass spectrometry method was used to quantify both POPEth, the clinically accepted biomarker, and six additional PEth homologues. A POPEth above the United States Drug Testing Laboratories (USDTL) cutoff was indicative of PAE up to 4 weeks pre-delivery. All PEth homologues were correlated to each other and logistic regression was used to determine the association between PAE status and infant characteristics. RESULTS Based on the sample, the rate of PAE, up to the last four weeks of gestation, in Ontario is estimated to be 15.5% (POPEth > 28.5 nM). Most PEth homologues were moderately to strongly correlated to each other. A low birth weight and preterm birth were both associated with PAE, while being small for gestational age had lower odds of PAE. CONCLUSIONS When compared to previous estimates of PAE by self-report or meconium testing, the results from this study suggest that PAE may be more prevalent. These findings support the need to consider the effectiveness of current interventions and the design of new interventions to address this significant public health issue.