Placenta as alternative specimen to detect in utero cannabis exposure: A systematic review of the literature

The use of cannabis during pregnancy and lactation is widely recognized as a health concern. The placenta is one of the several biological matrices that can be used to detect in utero drug exposure with the distinct advantage of easy and noninvasive collection. We conducted a PubMed search of selected literature published to June 30, 2016 to investigate the pharmacokinetics of cannabinoids, the active constituent of cannabis, in the placenta. The majority of the selected twelve papers was before 1990 and concerned animals at term gestation with great variability of experimental conditions. Only three were about human population and two of them reported equivocal findings on pre- term placenta. Our systematic review confirms that placental cannabis pharmacokinetics has been scarcely investigated and that further research is needed to determine advantages and disadvantages for monitoring maternal THC use or the degree of in utero exposure.