title: Prenatal exposure to cannabis and maternal and child health outcomes: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To assess the effects of use of cannabis during pregnancy on maternal and fetal outcomes.
  
  
  METHODS
  7 electronic databases were searched from inception to 1 April 2014. Studies that investigated the effects of use of cannabis during pregnancy on maternal and fetal outcomes were included.
  
  
  METHODS
  Case-control studies, cross-sectional and cohort studies were included.
  
  
  METHODS
  Data synthesis was undertaken via systematic review and meta-analysis of available evidence. All review stages were conducted independently by 2 reviewers.
  
  
  METHODS
  Maternal, fetal and neonatal outcomes up to 6 weeks postpartum after exposure to cannabis. Meta-analyses were conducted on variables that had 3 or more studies that measured an outcome in a consistent manner. Outcomes for which meta-analyses were conducted included: anaemia, birth weight, low birth weight, neonatal length, placement in the neonatal intensive care unit, gestational age, head circumference and preterm birth.
  
  
  RESULTS
  24 studies were included in the review. Results of the meta-analysis demonstrated that women who used cannabis during pregnancy had an increase in the odds of anaemia (pooled OR (pOR)=1.36: 95% CI 1.10 to 1.69) compared with women who did not use cannabis during pregnancy. Infants exposed to cannabis in utero had a decrease in birth weight (low birth weight pOR=1.77: 95% CI 1.04 to 3.01; pooled mean difference (pMD) for birth weight=109.42 g: 38.72 to 180.12) compared with infants whose mothers did not use cannabis during pregnancy. Infants exposed to cannabis in utero were also more likely to need placement in the neonatal intensive care unit compared with infants whose mothers did not use cannabis during pregnancy (pOR=2.02: 1.27 to 3.21).
  
  
  CONCLUSIONS
  Use of cannabis during pregnancy may increase adverse outcomes for women and their neonates. As use of cannabis gains social acceptance, pregnant women and their medical providers could benefit from health education on potential adverse effects of use of cannabis during pregnancy.
authors.affiliation: Department of Epidemiology and Biostatistics, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, Arizona, USA.
authors.forename: J K L
authors.initials: JK
authors.lastname: Gunn
authors.affiliation: Mel and Enid Zuckerman College of Public Health, University of Arizona, Phoenix, Arizona, USA.
authors.forename: C B
authors.initials: CB
authors.lastname: Rosales
authors.affiliation: Department of Obstetrics and Gynecology, University of Arizona, Tucson, Arizona, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Center
authors.affiliation: Arizona Health Sciences Library, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, Arizona, USA.
authors.forename: A
authors.initials: A
authors.lastname: Nuñez
authors.affiliation: Department of Health Promotion Sciences, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, Arizona, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Gibson
authors.affiliation: Arizona Department of Health Services, Phoenix, Arizona, USA.
authors.forename: C
authors.initials: C
authors.lastname: Christ
authors.affiliation: Department of Health Promotion Sciences, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, Arizona, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Ehiri
mesh_terms: D000740:Anemia / Q000453:epidemiology*; D001724:Birth Weight; D002188:Cannabis / Q000009:adverse effects*; D000067576:Child Health; D005260:Female; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008385:Marijuana Smoking / Q000009:adverse effects; D011247:Pregnancy; D047928:Premature Birth; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*
keywords: PREVENTIVE MEDICINE; PUBLIC HEALTH