New Method Developed to Detect Drug use During Pregnancy

Italian scientists Francesco Mari, Lucia Politi, and Elisabetta Bertol from the University of Florence have completed a systematic study of drug levels in the nails of newborn babies as an indicator of drug exposure during pregnancy. The scientists collected all fingernail and toenail clippings cut during the first three months of life of two sets of babies and pooled the samples for each individual. The first set consisted of 25 babies abandoned at birth and the second group comprised 33 babies born at the local maternity hospital.The clippings were cut into small pieces and spiked with nalorphine as an internal standard before incubation with dilute hydrochloric acid. The solution was extracted by solid-phase extraction and the extract was treated to convert the appropriate analytes to the trimethylsilyl derivatives for analysis by GC-MS. No interfering peaks were observed and the quantification gave linear curves over 0.05-0.4 ng/mg for methadone and 0.025-0.4 ng/mg for the other three drugs and metabolites. The detection limits were 0.025 ng/mg. Nicotine and its metabolite cotinine as well as caffeine were also analyzed.

Cocaine, benzoylecgoneine, morphine and methadone were found only in the abandoned babies in the ranges 0.14-0.25 ng/mg (6 samples). 0.12-0.20 ng/mg (6), 0.10-0.15 ng/mg (4) and 0.12-0.26 ng/mg (5). The samples containing morphine and methadone contained no other drugs. A total of 12 nail samples were positive for caffeine and 13 for both nicotine and cotinine.

Testing newborn nails for indications of prenatal drug exposure appears to be a viable option. It shows whether the fetus has been exposed but cannot give a timeline of exposure like that possible with the analysis of segmented hair samples. Nevertheless, it could provide valuable clinical information that will help to ensure the appropriate treatment for the newborn.