title: Identifying prenatal cannabis exposure and effects of concurrent tobacco exposure on neonatal growth.
abstract: BACKGROUND
  Cannabis is the most frequently used illicit drug among pregnant women, but data describing the effects of prenatal cannabis exposure and concurrent nicotine and cannabis exposures on neonatal growth are inconsistent. Testing of meconium, the first neonatal feces, offers objective evidence of prenatal cannabis exposure, but the relative ability of meconium testing and maternal self-report to identify affected neonates remains unclear.
  
  
  METHODS
  Eighty-six pregnant women provided detailed self-reports of daily cannabis and tobacco consumption throughout pregnancy. Cannabinoids and tobacco biomarkers were identified in oral fluid samples collected each trimester and quantified in meconium at birth.
  
  
  RESULTS
  Cannabis-using women were significantly more likely to also consume tobacco, and smoked similar numbers of cigarettes as non-cannabis-using tobacco smokers. As pregnancy progressed, fewer women smoked cannabis and those who continued to use cannabis reported smoking a smaller number of cannabis joints, but positive maternal oral fluid tests cast doubt on the veracity of some maternal self-reports. More neonates were identified as cannabis exposed by maternal self-report than meconium analysis, because many women quit cannabis use after the first or second trimester; meconium was more likely to be positive if cannabis use continued into the third trimester. Cannabis exposure was associated with decreased birth weight, reduced length, and smaller head circumference, even after data were controlled for tobacco coexposure.
  
  
  CONCLUSIONS
  Prenatal cannabis exposure was associated with fetal growth reduction. Meconium testing primarily identifies prenatal cannabis exposure occurring in the third trimester of gestation.
authors.affiliation: Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA.
authors.forename: Teresa R
authors.initials: TR
authors.lastname: Gray
authors.forename: Rina D
authors.initials: RD
authors.lastname: Eiden
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Leonard
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: Connors
authors.forename: Shannon
authors.initials: S
authors.lastname: Shisler
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Huestis
mesh_terms: D015415:Biomarkers / Q000032:analysis; D002186:Cannabinoids / Q000032:analysis; D005260:Female; D006130:Growth Disorders / Q000209:etiology*; D006801:Humans; D007231:Infant, Newborn; D002189:Marijuana Abuse / Q000150:complications*; D008431:Maternal-Fetal Exchange; D008470:Meconium / Q000737:chemistry; D011247:Pregnancy; D012907:Smoking / Q000009:adverse effects*
chemical_list: D015415:Biomarkers; D002186:Cannabinoids