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Medical cannabis and pregnancy – what you need to know



While doctors cannot prescribe cannabis during pregnancy in the UK, we know that thousands of women do continue to consume, for a variety of reasons.

We spoke to the experts – and the women who felt it was the right decision for them – to help others make an informed choice.

Cannabis use and pregnancy is a controversial topic – just as divisive, if not more so, when it comes to medicinal use.

In the UK, it’s highly unlikely that any clinician would continue to prescribe cannabis throughout a woman’s pregnancy or while she was breastfeeding. The general guidance is to refrain from consumption, as there simply isn’t enough scientific evidence to say one way or another what the effects, if any, on the baby might be.

This article is in no way promoting or encouraging the use of cannabis during pregnancy. It is, however, going to talk about it, with insight from experts, existing research and the experiences of women who have done, on why it was right for them.

The fact is, that thousands of women are continuing to use cannabis throughout pregnancy, because they feel that in their case, the potential benefits outweigh any potential risks. They should be able to make an informed choice about what’s right for them, and currently many feel ill-equipped to do so.

So, why do women consume cannabis during pregnancy?

A Canadian study published last year provided some rare insight into the motivations of those who chose to consume cannabis during their pregnancy. The study included over 50 women and one non-binary person, recruited from across Canada, 30 of whom were pregnant and 22 breastfeeding.

It found that those who continued to consume did so to manage pregnancy-related symptoms and pre-existing conditions,​​ including pain management, anxiety, depression, muscle spasms, nausea or appetite, and sleep, with many using it to manage multiple symptoms.

This was interesting, as for the first time it addressed the reasons why people might continue to consume, which researchers described as ​​”more closely matching those identified in studies of medical cannabis use”.

Elsewhere, studies are thought to be ongoing into the use of cannabis for hyperemesis, the medical term for severe nausea and vomiting during pregnancy. The symptoms can be debilitating with some sufferers vomiting throughout the day, becoming dehydrated, dizzy and unable to keep food down, losing significant amounts of weight as a result. Vaping cannabis is known to reduce symptoms of nausea and may help with keeping food down, but nothing has been published to date.

Conflicting data

The evidence base around the effects of cannabis on birth outcomes and perinatal health has been growing in recent years, spurred on by legalisation in Canada and increasing numbers of states across the US. But the findings are inconsistent.

Some observational data has identified a link between exposure and low birth weight and/or an increased risk of preterm birth. However, others have failed to substantiate these claims once adjusting for other factors, such as tobacco smoking.

Meanwhile, a more recent study came up with something different, linking foetal cannabis exposure to higher risk of obesity in childhood. 

Dr Rebecca Moore, a perinatal psychiatrist and founder of the Make Birth Better campaign, who has been prescribing medical cannabis since 2018, says it’s difficult to know how much to read into these studies.

Dr Rebecca Moore

Often they include small sample sizes and have not accounted for confounding factors such as tobacco use or family history, or fail to state what amounts of cannabis the participants were using.

“The difficulty is, that we don’t really know what THC does to a developing foetus, because we just don’t have enough data to be able to make any causal links”, says Dr Moore.

“I would like to see more up- to-date, relevant data around women who use cannabis in pregnancy, because a lot of these studies are quite old.”

Now is probably a good time to point out that most studies in this area have been done on recreational cannabis. Despite a few looking at medical use, none have focused on prescribed cannabis, due to the fact that doctors are not able to prescribe.

“It’s a bit conflicting, because the advice is that you shouldn’t use it,” continues Dr Moore.

“But we’re in a place where we know that lots of people do and there are a lot of people who want to be able to make a more balanced risk assessment.”

She continues: “I see people who say they have used it all the way through pregnancy and were completely fine, but it’s not something that as a prescribing doctor we could recommend. The honest answer is, we just don’t know for sure.”

“I spend my whole day weighing up the risk benefit, but what it comes down to is people being informed, so they feel that they can make their own choice.”

Dr Rebecca Moore

Instead, Dr Moore sits down with her patients and explains the lack of literature around it, pointing them in the direction of a handful of good, more recent studies.

One of which is a longitudinal study published last year in Norway, on a sample of around 10,000 women. It found a “clinically relevant association” between the use of cannabis during pregnancy and reduced birth weight.

Again this study looked at recreational cannabis, usually accessed through the illicit market, which tends to contain higher levels of THC than that which is medically prescribed.

“I spend my whole day weighing up the risk vs benefit, but what it comes down to is people being informed, so they feel that they can make their own choice,” Dr Moore adds.

“If you’re planning a pregnancy or you find yourself pregnant, speak to your provider immediately, so that you can go through all the risks and benefits.”


“I weighed up the pros and cons and the risk of having a seizure”

For some women, who rely on cannabis for medical reasons, the risk of continuing to consume it may be outweighed by that of the alternative – which could be using street cannabis or other prescription drugs which could have potential harms of their own. Similarly, not using cannabis may have a greater impact on the health of the mother and child.

Callie Seaman, of Medcan Support, whose son is about to turn 18, made the choice to continue to consume cannabis throughout her pregnancy to manage her epilepsy.

Callie had been using cannabis medicinally since she was diagnosed with the condition in her teens and felt that the risk of having a seizure while pregnant and harming the baby, was worse than any potential risks of the cannabis.

Callie Seaman

“I weighed up the pros and the cons, and the risk of having a seizure and the damage that would do to the baby was far greater,” she says.

“I wouldn’t promote using it, but on the flip-side many women have continued to use anti-epileptic drugs during pregnancy. One in particular, sodium valproate, has been found to cause some birth defects.”

She adds: “I don’t have any regrets. My son was a healthy eight pound baby and neither of us had any health issues.”

“Many women have continued to use anti-epileptic drugs during pregnancy, one in particular, sodium valproate, has been found to cause some birth defects.”

Callie Seaman

The cannabis also helped her manage the stress and anxiety of a pregnancy which was unplanned.

“Pregnancy is a very stressful time for many women,” she continues.

“It helped a lot to keep my anxiety levels down. I don’t think I’d have gotten through it without it.”

While Callie’s family were supportive, she didn’t feel comfortable talking to health professionals about her decision, saying she “didn’t dare mention it to anyone else”.

Callie and her son, now 18

She also took measures to reduce any potential harm, looking for alternative ingestion methods and moving from smoking to vaping without tobacco.

“Weigh up the pros and cons and if your condition dictates that you need to consume, remove risks like smoking and look at moving onto tincture,” she explains.

“Make sure you know what you are taking, that it is a balanced product, from a reliable source and that they’ve got certificates of analysis.”

She adds: “It was 2004 when I was pregnant, we didn’t have the industry we have now. One of the first things I would recommend is to speak to your medical cannabis clinician and seek their advice.”

Perinatal depression

“I was so miserable, it was inhibiting my ability to really care for myself the way I needed to”

In the US, where cannabis has been legalised in many states, more women are open about their choice to consume.

Beth*, who lived in the US at the time, didn’t plan to consume throughout her pregnancy, but made an informed choice when she began experiencing severe perinatal depression early on.

“I started to feel overwhelmingly depressed and anxious,” she says.

“I knew I needed to do something because I was so miserable, it was inhibiting my ability to really care for myself the way I needed to, as someone who was growing a child inside of them.”

Beth continues: “I spoke to my doctors about it but they wanted to put me on antidepressants. I ended up doing my own research. The links to autism, and the fact that they need to be used continually to be effective, concerned me.

“I weighed up the pros and cons, and it wasn’t without concern, but once I made the decision, I went forward with it.

“I used edibles and tinctures and I used it sparingly, just when I needed to. My goal wasn’t to get high, it was just to take away some of the symptoms so I could look after myself properly.”

“My goal wasn’t to get high, it was just to take away some of the symptoms so I could look after myself properly.”


Beth was open with her healthcare provider, but after the birth she was forced to undergo a drug test and speak to a social worker.

“It was the most terrifying thing for a new mum to hear,” she recalls.

“I had been honest and as a result I was going to have my child taken away.”

But when they tested the baby for cannabis they found no trace of it.

Beth adds: “I think that raises the question of, how does it actually affect the baby?”

Harm reduction

Dr Dani Gordon, a Canadian British doctor now practising in the UK and a leading expert in prescribing cannabinoids, admits that there is nothing “totally alarming” in the existing studies on pregnancy and recreational cannabis use.

“There’s nothing totally alarming there, but there may be subtle neurocognitive effects we just don’t know about, in addition to a potential effect on birth weight which is important, if not alarming” she says.

Dr Dani Gordon

“I would be surprised if there were not some sort of effect, especially at high doses, because we think that the endocannabinoid system in the developing brain is quite sensitive”

Dr Gordon has recently opened her own clinic, which focuses on integrative medicine, and is an authoritative voice on the use of cannabis medicines in women’s health.

“The message to women is really confusing, we want to empower them to make their own choices, but in order to be empowered, they have to have the pros and the cons, and in this case, we don’t know them all,” she says.

“We don’t know if the risk of keeping someone who has anxiety and PTSD on cannabis, is going to be less than the risk of going back to medications that they were on before, such as benzodiazepines. Plus foetal exposure to the stress hormone also has deleterious effects on unborn babies.”

Even in cases such as those described in this article – where a clear risk vs benefit decision has been made – they would be unlikely to stand up legally in the UK.

Dr Gordon continues: “As a doctor we have to fall back on the oath ‘to do no harm’, and that is even more important when it comes to cannabis medicine, because we know less than we do with conventional drugs.

“In the cases that are really murky, it comes down to whether if I prescribed, what would a jury of my peers say? There might be more support for it in Canada [where medical cannabis has been legal since 2001] but certainly in the UK the stance would be that there is no evidence for this.”

“As a doctor we have to fall back on the oath ‘to do no harm’, and that is even more important when it comes to cannabis.”

Dr Dani Gordon

But while they can’t prescribe or be seen to condone cannabis use, doctors can still take a harm reduction approach with patients, according to Dr Gordon.

“I would ask people where they are accessing their cannabis from. I would tell them that vaporising cannabis is a lower risk for you and your baby than smoking, and I would suggest they get a sample tested to make sure it doesn’t contain anything it shouldn’t,” she says.

“Then it’s about CBD vs THC ratios. We don’t know, but based on very preliminary evidence, I suspect that lower THC and higher CBD is safer.”

While there is still no data on the use of CBD alone and doctors couldn’t recommend perinatal use, according to Dr Gordon in cases of harm reduction or use in conditions such as epilepsy or panic disorder, where other pregnancy-safe drugs have failed, there may be an argument to be made, if a doctor had support from a panel of their peers.

“What’s worse than maternal cannabis use, is maternal cannabis use combined with guilt and shame.”

Dr Dani Gordon

After the birth, many women feel they want to breastfeed their babies for health reasons, but just as in pregnancy, clinicians would be unwilling to prescribe due to the lack of evidence.

Dr Gordon tries to encourage patients to take a balanced approach, for example, pumping milk in advance and monitoring them on a weekly basis, making sure they feel it’s okay to stop if the benefit is outweighed by the harm it’s causing to the mother.

“There’s so much pressure to breastfeed, I experienced it myself,” she says.

“We need to remove the guilt and shame. What’s worse than maternal cannabis use, is maternal cannabis use combined with guilt and shame and high stress hormones.”

Alternative options?

Accessing legally prescribed cannabis may be out of the question for women in the UK at this point in their lives, but there may be other alternatives.

As an integrative medicine doctor Dr Gordon has a range of treatments available which may help and are safe for use during pregnancy.

“I would encourage people to get expert medical advice, because with integrative medicine, there are a range of other options that are safe and effective during pregnancy. These include supplements, meditation techniques, even electro stimulation devices which people can get for home use,” she adds.

“If cannabis is not for them, or it’s not for them right now, we can find something to alleviate their symptoms until it is.”

*Beth’s name has been changed to protect her identity

Sarah Sinclair is a respected cannabis journalist writing on subjects related to science, medicine, research, health and wellness. She is managing editor of Cannabis Health, the UK’s leading title covering medical cannabis and CBD, and sister title and Psychedelic Health. Sarah has an NCTJ journalism qualification and an MA in Journalism from the University of Sunderland. Sarah has over six years experience working on newspapers, magazines and digital-first titles, the last two of which have been in the cannabis sector. She has also completed training through the Medical Cannabis Clinicians Society securing a certificate in Medical Cannabis Explained. She is a member of PLEA’s (Patient-Led Engagement for Access) advisory board, has hosted several webinars on cannabis and women's health and has moderated at industry events such as Cannabis Europa. Sarah Sinclair is the editor of Cannabis Health. Got a story? Email / Follow us on Twitter: @CannabisHNews / Instagram: @cannabishealthmag


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