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Medicinal cannabis use during pregnancy is a topical issue for both practitioners and patients to address. As medical cannabis prescriptions increase around the globe, the necessity to have a deeper understanding of the impact and risks of cannabinoids on fertility, pregnancy and postnatal health is of supreme importance.

For further CBD training, you may be interested to learn more about the HealthCert Professional Diploma program in Medicinal Cannabis, allowing you to get your medical cannabis certification online.

Medicinal cannabis stats for Australian women

Cannabis is the most frequently used illicit drug in Australia. According to the National Drug Survey conducted in 2016, approximately 10% of women of reproductive age had ingested cannabis in the previous 12 months.

The University of Adelaide recently published a study of over 5500 women across Australia, New Zealand and the United Kingdom. 5.6% (n=314) of women ingested cannabis before or during pregnancy according to results. Of those 314 individuals, 31% ceased before becoming pregnant, 50% stopped cannabis use before the 15-week mark and 19% continued past 15-weeks gestation.

As the prevalence of both medicinal cannabis and adult use increases, the need for quality and relevant research into the impact of cannabinoids on fertility, pregnancy and the child is desperately required if we are to understand how these commonly consumed compounds are impacting a significant number of individuals across our population.

What are the risks of medicinal cannabis and recreational cannabis during pregnancy?

The difficulty in assessing information on the effect of medical cannabis on pregnancy is that the human research available pertains to pregnant women ingesting recreational cannabis, predominantly through smoking and often with the addition of other confounding risks. Many of the conclusions drawn from such research do not account for the negative impacts associated with tobacco or alcohol separate to medical cannabis or recreational cannabis intake.

Regardless, the known risks associated with recreational cannabis use during pregnancy may include an increased risk of ectopic pregnancy, premature delivery, low birth weight and an increased likelihood of cannabis use during adolescence.

Health risks associated with tobacco smoking and alcohol intake during pregnancy include a higher chance of negative events such as preterm delivery, placenta problems, low birth weight and birth defects amongst others. Data suggests that of women using recreational cannabis during pregnancy, approximately 65% concurrently smoked tobacco and 85% drank alcohol, with 29% having more than one drink per day.

While there are clear risks and uncertainty in relation to cannabis use during pregnancy, this data shows the significant crossover with recreational cannabis use to other behaviours that are known to negatively impact the growing child.

This highlights the need to critically evaluate evidence surrounding the direct effect of cannabinoids on pregnancy, and whether medicinal cannabis specifically has any negative impact on the foetus.

The Endocannabinoid System and fertility

The Endocannabinoid System (ECS) is widely recognised in research, yet much of the understanding we have of this unique system has yet to be transferred into clinical practice. In adults, we know that the ECS has great influence over mood, immune responses, digestive function and memory processes.

This system is a part of every individual whether they’ve consumed cannabis in their lifetime or not and consists of two main receptors CB1  and CB2. These receptors influence body processes through the action of endocannabinoids, compounds that the body produces innately; and are influenced by exogenous cannabinoids, from botanical or synthetic sources.

Both CB1  and CB2 receptors are found in the female reproductive organs, with local endocannabinoid levels fluctuating with a woman’s cycle. There are theories that dysregulation in the ECS can have far-reaching effects on numerous health outcomes.

In animal research, the endocannabinoid anandamide is thought to have an impact on successful implantation in its influence over uterine receptivity. Exogenous cannabinoids are thought to interact with the ECS and have been shown to induce muscle relaxation in the fallopian tubes of mice, decreasing the motility of the fertilised egg toward the uterus.

While there is a potential for deviations in endocannabinoid signalling to impact the uterine environment and other processes affecting fertility, translational research interpreting animal investigations of the ECS in the context of human fertility has yet to be conducted and as such, we cannot draw definitive conclusions.

The impact of CBD and THC on pregnancy and foetal measures

There are numerous ways in which we think cannabinoids may impact pregnancy. Nutritionally folate (or the synthetic form, folic acid) is essential for human health and especially important during pregnancy. Having adequate maternal levels of folate in the lead up to pregnancy is also associated with optimal foetal development as the nutrient plays an integral role in cell differentiation, DNA and RNA synthesis.

Both CBD and THC have been investigated for their capacity to decrease uptake of folic acid in human cell lines simulating chronic cannabis use. Similar in-vitro research points to cannabinoids reducing levels of other important cellular growth factors – however this is early stage research.

Given the rapid cell differentiation and development during pregnancy, the impact that medical cannabis may have on the growth and development of the foetus would need to be addressed with further studies.

Physiological pathways activated by cannabis compounds that are being investigated for their potential antitumor effects by decreasing cell migration and disrupting the growth of new blood vessels are the same pathways that may pose harmful effects on pregnancy. It is important to note that these actions have yet to be correlated with pregnancy outcomes.

Smoking cannabis and the growing child

Smoking continues to be the primary route of ingestion of cannabis in a recreational setting. It is the process of combustion that poses the greatest concern when smoking. Combustion creates numerous toxic substances such as carbon monoxide and reactive oxygen species, which increases toxic load and requirements for antioxidants. These compounds are known to play a role in the expression of sub-fertility among couples, as well as having a negative effect on the growing child.

Risks of recreational cannabis during pregnancy

As mentioned there are clear risks in terms of recreational cannabis during pregnancy. A number of studies report an increased incidence of preterm birth and NICU requirements amongst mothers who consumed cannabis during pregnancy. However, a 2016 systematic review and meta-analysis came to different conclusions.

When pooling data from 31 studies, the meta-analysis showed cannabis use had negative impacts on birth weight and delivery date. However, when adjusted for the effects of alcohol, tobacco and other illicit substances, the authors found there was no statistically significant evidence of recreational cannabis affecting birth weight, preterm delivery or size for gestational age.

The aforementioned 2020 study conducted by the University of Adelaide contradicted the above meta-analysis. It concluded cannabis use was associated with poor foetal outcomes in terms of birth length, weight, gestational age and risk of morbidity, independent of tobacco use. However, for those women that ceased cannabis use during early pregnancy, there was less risk of adverse effects.

In relation to other complications common during pregnancy, cannabis use is not likely to be associated with increased risk in pre-eclampsia, postpartum haemorrhage, gestational diabetes or gestational hypertension, but given the lack of  research in this area, we can never rule it out.

Foetal ECS and THC risk

The ECS in the foetal brain begins to establish from 14 weeks gestation and plays a big role in the development of neuronal connectivity and signalling. In terms of pregnancy, the greatest concern is the impact of THC, the primary intoxicating cannabinoid.

Extrapolations from animal studies indicate THC readily crosses the placental barrier and has relatively slow clearance. How this primary and intoxicating cannabinoid might interact with the foetal ECS and impact development is largely unknown, what we do know is optimal foetal developmental processes exist within a tightly regulated range.

While foetal and maternal endocannabinoids are likely to play a significant role in the healthy development of the foetus, exogenous cannabinoid exposure at critical points of neurodevelopment could have a deleterious effect and must be further investigated.

The ethics of medical cannabis research on pregnant women

While in general the application of medical cannabis in a supervised and clinically appropriate manner is vastly different to the effects illicit cannabis use has on the body, in the case of pregnancy that point proves relatively moot. Given the inherent risk and evidence tending towards recreational cannabis having a negative effect on pregnancy, there is little foundation to support investigating the application of pharmaceutical-grade medical cannabis during pregnancy.

Simply put, it may be considered unethical, even if researching the impact of medical cannabis is important. Therefore our understanding is limited to extrapolations from animal studies and observational research of pregnant women using illicit cannabis, or in some international cases, legally accessed recreational products.

Can medical cannabis help with nausea during pregnancy?

Given the association with treating symptoms of nausea with medical cannabis, it is understandable there is interest in how medical cannabis might be able to help alleviate nausea during pregnancy, particularly for those women struggling with hyperemesis gravidarum.

The clinical outcomes observed in utilising medicinal cannabis for nausea relief has generally been limited to chemotherapy-related presentations. Whether synthetic or botanically derived, it is the THC component that is largely responsible for the anti-nausea action of cannabis. Irrelevant to other concerns surrounding cannabis intake during pregnancy, the extent of negative effects of THC on the growing foetus and subsequent development of the child, is unknown and is therefore avoided in a clinical setting.

Taking CBD oil during pregnancy

Few international physicians believe that well monitored application of CBD oil during pregnancy may be beneficial. Anecdotally women have reported CBD oil during pregnancy to help with symptoms such as nausea, vomiting, sleeplessness and pain. Despite symptoms such as these being sometimes treated as an adjunct therapy with medical CBD oil in other settings, medical professionals err on the side of caution in the instance of pregnancy.

The wrap-up on medicinal cannabis and pregnancy

Conflicting evidence and lack of trials outside an observational setting makes it difficult to assess the direct impact of specific cannabinoids on pregnancy and foetal outcomes. In general, any substance that impacts the delicate balance of maternal physiological processes has the capacity to impact the baby, and as such, clinicians will caution against its use.

For further CBD training, you may be interested to learn more about the HealthCert Professional Diploma program in Medicinal Cannabis, allowing you to get your medical cannabis certification online.

Read another article: Medicinal cannabis and chronic back pain

If you are interested in becoming an authorised prescriber of Medicinal Cannabis in Australia, the TGA SAS-B guidelines require you to prove that you have the knowledge necessary to do so. HealthCert’s Professional Diploma of Medicinal Cannabis pathway can serve as part of your documentation showing that you have undertaken education in this field when you decide to become an authorised prescriber.

This article has been provided by our partner, Southern Cannabis Holdings. Southern Cannabis Holdings builds, integrates and operates high-value brands across the cannabis value chain, including FreshLeaf Analytics, Cannabis Access Clinics and Applied Cannabis Research. HealthCert and Southern Cross Holdings have partnered up to bridge gaps in patient and clinician knowledge on medicinal cannabis.

Contact CA Clinics at info@caclinics.com.au or call 1300 991 477 if you would like more information.

DISCLAIMER: Medicinal cannabis products are unapproved therapeutic goods, which means they have not been assessed by the TGA for safety, quality or effectiveness. However, where clinically appropriate, there are pathways for doctors to access medicinal cannabis products for their patients. Note that medicinal cannabis does not have therapeutic effects for all patients and may not be medically appropriate for your patients’ conditions. Some patients may experience side effects. None of the content here is an encouragement or inducement to try or use medicinal cannabis, and is for educational and informational purposes only.