The impact of using cannabis during pregnancy on the infant and mother: An overview of systematic reviews, evidence map, targeted updates, and de novo synthesis

Background: Cannabis use during pregnancy is becoming more prevalent. While numerous studies have explored the relationship of cannabis use during pregnancy and outcomes for mothers and infants, uncertainty remains regarding the impact of cannabis use on pregnancy complications and later-life outcomes for offspring.

Aims: To produce a summary of the short and long-term effects of prenatal cannabis exposure on fetal growth and development, neonatal conditions, later-life, and maternal outcomes.

Materials and methods: An overview of systematic reviews, an evidence and gap map, targeted updates of previous reviews, and de novo evidence synthesis was conducted. The databases searched include PubMed (National Center for Biotechnology Information); MEDLINE (Ovid); Embase (Ovid) and CINAHL with Full Text (EBSCO). Assessment of risk of bias was conducted in duplicate for all studies. Relevant studies were coded and are presented as an evidence and gap map. Where possible, meta-analyses were conducted with a narrative synthesis of the results. Primary studies and systematic reviews examining the relationship between cannabis consumption in pregnancy and the effect on fetal/child development, antenatal, and obstetric outcomes during pregnancy were eligible for inclusion.

Results: There were 89 studies/reviews eligible for inclusion in this review. There was a potentially harmful impact of prenatal cannabis exposure on all fetal growth and development outcomes, some neonatal outcomes, some later-life outcomes, and some maternal outcomes. The evidence regarding other neonatal conditions, later-life, and maternal outcomes was mixed.

Conclusions: The evidence suggests cannabis should be avoided during pregnancy.