Animal Models Evaluating the Impact of Prenatal Exposure to Tobacco and Marijuana

The association between prenatal cannabis use and congenital birth defects in offspring: A cumulative meta-analysis

OBJECTIVE

To examine the association between prenatal cannabis use and structural birth defects in exposed offspring.

METHODS

In line with the preregistered protocol (PROSPERO: CRD42022368623), we systematically searched PubMed/Medline, CINHAL, EMBASE, Web of Science, ProQuest, Psych-Info, and Google Scholar for published articles until 25 January 2024. The methodological quality of the included studies was appraised by the Newcastle-Ottawa Quality Assessment Scale (NOS). A meta-analysis was carried out to report the pooled effect estimates from the included studies. We further performed subgroup, leave-one-out sensitivity, and meta-regression analyses, which increased the robustness of our findings.

RESULTS

In this cumulative meta-analysis, thirty-six observational studies, consisting of 18 case-control and 18 cohort studies, with 230, 816 cases of birth defects and 18,049,013 controls (healthy babies) were included in the final analysis. We found that offspring exposed to maternal prenatal cannabis are at greater risks of a wide range of structural birth defects: cardiovascular/heart [OR = 2.35: 95 % CI 1.63 - 3.39], gastrointestinal [OR = 2.42: 95 % CI 1.61 - 3.64], central nervous system [OR = 2.87: 95 % CI 1.51 - 5.46], genitourinary [OR = 2.39: 95 % CI 1.11 - 5.17], and any (unclassified) birth defects [OR = 1.25: 95 % CI 1.12 - 1.41].

CONCLUSION

The findings from the current study suggest that maternal prenatal cannabis exposure is associated with a higher risk of different forms of structural birth defects in offspring. The findings underscore the significance of implementing preventive strategies, including enhanced preconception counselling, to address cannabis use during pregnancy and mitigate the risk of birth defects in offspring.

The impact of pregnancy and associated hormones on the pharmacokinetics of Δ9-tetrahydrocannabinol

INTRODUCTION

(-)-Δ9-tetrahydrocannabinol (THC) is the main psychoactive component of cannabis. Cannabis is the most widely used drug of abuse by pregnant individuals, but its maternal-fetal safety is still unclear. The changes in THC disposition during pregnancy may affect THC safety and pharmacology.

AREAS COVERED

This review summarizes the current literature on THC metabolism and pharmacokinetics in humans. It provides an analysis of how hormonal changes during pregnancy may alter the expression of cannabinoid metabolizing enzymes and THC and its metabolite pharmacokinetics. THC is predominately (>70%) cleared by hepatic metabolism to its psychoactive active metabolite, 11-OH-THC by cytochrome P450 (CYP) 2C9 and to other metabolites (<30%) by CYP3A4. Other physiological processes that change during pregnancy and may alter cannabinoid disposition are also reviewed.

EXPERT OPINION

THC and its metabolites disposition likely change during pregnancy. Hepatic CYP2C9 and CYP3A4 are induced in pregnant individuals and in vitro by pregnancy hormones. This induction of CYP2C9 and CYP3A4 is predicted to lead to altered THC and 11-OH-THC disposition and pharmacodynamic effects. More in vitro studies of THC metabolism and induction of the enzymes metabolizing cannabinoids are necessary to improve the prediction of THC pharmacokinetics in pregnant individuals.