Cannabis in Pregnancy: Is It Safe?
Some women use cannabis before finding out they're pregnant, and others consider it for nausea or anxiety once they are. NHS guidance is clear that cannabis is not recommended in pregnancy, in any form, and this page sets out why — without judgement — and what to do if you've already used it or want support to stop.
Why Cannabis Isn't Recommended in Pregnancy
Cannabis crosses the placenta, meaning THC (its main psychoactive compound) reaches your baby's bloodstream too. Research on human pregnancy is limited and hard to study cleanly, but the evidence that does exist has raised enough concern that UK and NHS guidance advises avoiding cannabis completely during pregnancy and while breastfeeding. Associations raised in research include lower birth weight, premature birth, and possible effects on a baby's developing brain and later behaviour, though the full picture isn't settled. Because the risk can't be ruled out, the advice is to avoid it rather than assume any particular method or amount is fine.
Smoked Cannabis Specifically
If cannabis is smoked, often mixed with tobacco, it carries the additional risks of smoking in pregnancy on top of the effects of THC itself. Cannabis smoke contains many of the same harmful chemicals as cigarette smoke, including carbon monoxide, which reduces the oxygen reaching your baby — a separate reason smoked cannabis is discouraged, distinct from concerns about THC alone.
What About CBD?
CBD (cannabidiol) products — oils, gummies, capsules — are marketed as non-intoxicating and separate from "cannabis", but current UK guidance does not consider them proven safe in pregnancy either. CBD products are unregulated as medicines, so what's actually in a bottle, including any THC content or contaminants, isn't guaranteed. The safest approach is to avoid CBD in pregnancy too, and speak to your midwife or GP about safer alternatives for the symptom you're trying to manage.
What to Do If You Use Cannabis or Want to Stop
- Talk to your midwife or GP — they are there to support you, not to judge, and disclosing use helps them monitor your baby's growth appropriately.
- If you've already used cannabis earlier in pregnancy, particularly before you knew, try not to panic: bring it up at your next appointment so your care team has the full picture.
- Ask about local drug and alcohol support services, which can offer confidential help tailored to pregnancy.
- If cannabis is being used to manage a specific symptom such as nausea, sleep problems or anxiety, ask about pregnancy-safe alternatives — there are often other options that don't carry the same uncertainty.
Frequently Asked Questions
Is any amount of cannabis safe in pregnancy?
No safe amount or safe stage of pregnancy for cannabis use has been established, so NHS guidance is to avoid it altogether. THC crosses the placenta to your baby, and research has raised concerns including lower birth weight and effects on development. If you've used cannabis, talk to your midwife or GP rather than assuming a single or early use has caused harm.
Is CBD oil safer than cannabis in pregnancy?
CBD is not established as safe in pregnancy and current guidance is to avoid it too. CBD products are not regulated as medicines, so their exact contents (including any THC) aren't guaranteed, and there isn't enough research to say they're risk-free. Speak to your midwife or GP about safer ways to manage the symptom you're using CBD for.
Will my baby have withdrawal symptoms if I've used cannabis in pregnancy?
Regular cannabis use in pregnancy has been linked to newborns showing signs of withdrawal or irritability after birth in some cases, though this varies. Telling your midwife about your use, the sooner the better, means your baby's care team can watch for this and support you both. This is a medical, not judgemental, conversation.
This article is for informational purposes only and does not constitute medical advice.
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