[Value of toxicological research in newborn infants of addicted mothers by the study of several samples (urine, meconium, hair)]

Abstract

Background: Urinary detection of prenatal drug exposure in the neonate may give false-negative results. We report our experience on meconium and hair testing, in addition to urine testing in order to improve diagnosis of fetal drug exposure.

Population and methods: Thirty-one infants (aged 1-45 days) whose mothers were confirmed (n = 12) or suspected (n = 19) to be drug-addicted were included in the study. One or more specimens of urine, meconium or hair were collected in the 31 infants, two of the specimens in 17 and three in six. Drugs and their metabolites were detected by immunoenzymologic techniques and positive results were confirmed by gas-exchange chromatography. All the mothers and families were interviewed during admission and the information was compared to those provided by medical and social services; the results of laboratory analysis were not known by the investigators at this time of the study.

Results: The maternal drug addiction was confirmed after clinical investigation in 18 cases including the 12 cases detected by prenatal interview (group 1), and recused in 13 other cases (group 2). In group 1, nine infants of 12 had a positive urine test (seven opiate, one cocaine, one cannabis), 11 of 11 a positive meconium test (nine opiate, one cocaine, one cannabis), ten of 19 a positive hair test (eight opiate, one cocaine, one cannabis); all infants in this group had at least one positive result. In group 2, all tests were negative except one urine test positive for opiate after cesarean delivery performed under anesthesia including opiate analgesia.

Conclusions: Urine, meconium and hair testing versus urine testing alone increase the sensitivity of laboratory analysis for detection of prenatal drug exposure.