Cocaine detection in maternal and neonatal hair: implications to fetal toxicology
Authors: Gideon Koren
Ben Rokach
Tatyana Karaskov
Facundo Garcia-Bournissen
Journal: Therapeutic drug monitoring (2007)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: Cocaine; pregnancy; maternal reports; fetal exposure; adverse effects
Affiliations: Motherisk Program, Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, University of Toronto, Toronto, Canada.

Abstract:  Cocaine use during pregnancy is difficult to ascertain, and maternal reports are likely to be inaccurate. Presently, the dose-response characteristics between maternal cocaine use and fetal exposure and adverse effects are unknown. Clinically, some babies are harmed, whereas others are not adversely affected. Taking advantage of the fact that cocaine and its metabolite benzoylecgonine (BE) accumulate and can be detected months after exposure in maternal and neonatal hair, an analytical test for cocaine and BE was developed by the authors. The aim of this study was to describe the characteristics of maternal and neonatal hair cocaine as biomarkers of fetal exposure. Of nearly 10,000 cases, all mother-child pairs in whom at least one had cocaine and/or BE detected in hair were identified. The relationship between maternal and neonatal levels was studied. When available, these data were also compared with meconium levels of cocaine. Median cocaine concentration was 10-fold higher in hair of the mothers compared with the neonates (3.56 ng/mg vs 0.31 ng/mg of hair). Infants' cocaine in hair was positively correlated with maternal cocaine and BE in hair (r2 = 0.41 and r2 = 0.22, respectively, P &lt; 0.001 for both correlations). Infants' BE was also correlated with maternal cocaine and BE concentrations in hair (r2 = 0.50 and r2 = 0.27, P &lt; 0.001 for both correlations). Thirty-nine (40%) babies had negative cocaine and BE results despite their mothers being positive. Mothers whose infants were cocaine-positive had a median hair cocaine concentration of 7.34 ng/mg, significantly higher than those whose infants were negative (1.25 ng/mg). Maternal cocaine levels below 0.24 ng/mg may serve as a relative threshold for detectable fetal exposure during the third trimester of pregnancy. Fetal hair grows in the last trimester. Hence, a positive neonatal hair indicates maternal use after pregnancy became known, a strong indicator of maternal addiction. Transplacental exposure to cocaine of babies of addicted mothers is highly variable. The dose-response relationship of both cocaine and BE between maternal and neonatal hair suggests that the placenta protects some fetuses but not others. More research is needed to understand the mechanisms leading to placental defense against cocaine. 

Retracted: No

PubPeer comments:
 Corrected [April 2017] :  In the February 2007 issue of *Therapeutic Drug Monitoring*, the article u201cCocaine Detection in Maternal and Neonatal Hair: Implications to Fetal Toxicologyu201d contains some potentially misleading information. This paper may be read to imply that all positive RIA and ELISA samples were confirmed with GC-MS. Some, but not all positive samples were confirmed with GC MS. This had no impact on the results of comparing maternal to neonatal hair levels in the paper and the paperu2019s conclusions remain the same. Expression of Concern [September 2017] .  Regarding the February 2007 article u201cCocaine Detection in Maternal and Neonatal Hair: Implications to Fetal Toxicologyu201d,1 and its erratum of April 2017,2 the editors have a remaining concern that was not fully addressed by the Erratum. The main issue in the original February 2007 paper on a late-phase translational study published in *Therapeutic Drug Monitoring* is that the text suggested that all ELISA positive samples had been confirmed by GC-MS. The authors acknowledged in their April 2017 Erratum that this was not the case. Personal communication with the authors has shown that, in fact, ELISA test results were confirmed by GC-MS in only about 10% of the samples (54 out of 531). Therefore, there is still a possibility that results obtained by ELISA may have differed from GC-MS results in some cases. ,