Cannabis is a commonly used recreational drug prepared from dried leaves and flowers or resinous extracts of plants which contain psychoactive compounds known as cannabinoids; primarily Δ9-tetrahydrocannabinol (Δ9-THC), cannabinol and cannabidiol. Cannabis is most commonly smoked, ingested, or, on rare occasions, injected. A preparation containing a mixture of Δ9-THC and cannabidiol is available in the UK licensed as a controlled medication for the treatment of moderate to severe spasticity in adult patients with multiple sclerosis.
The available data concerning maternal cannabis use in pregnancy are considered to be both methodologically limited and confounded, and, as such, caution is advised in the interpretation of the study findings.
Although there is no conclusive evidence to suggest an association between maternal cannabis use and an increase in the overall congenital malformation rate, possible associations with specific malformations including gastroschisis and ventricular septal defects have been described in a small number of case-control studies. Possible associations with stillbirth, preterm delivery, impaired fetal growth and neurodevelopmental impairments have also been described. However, the relative contributions of concomitant risk factors, including but not limited to maternal tobacco smoking, are currently unclear.
Exposure to cannabis at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring. However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.
This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.
If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.
If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.