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Congenital Birth Defects Caused by Cannabis

Updated: Nov 8, 2022

This article summary was written by Dr. Stuart Reece and published on this site with Dr. Reece's permission. Minor edits were made for grammar, section breaks, etc. that did not affect content or meaning. Please note this article contains an actual image of an infant with one of the birth defects described.


This paper looks at the patterns of disease occurrence, which scientists call “epidemiology”. It studies defects in the body wall in newborn babies across 14 nations of Europe during 2010-2019.

The body wall defects investigated were two defects in the belly button – called gastroschisis and omphalocele – and one defect in the diaphragm – called diaphragmatic hernia. These birth defects cause the bowels to hang outside the abdomen.

Body wall birth defects have previously been linked with cannabis exposure in many studies including in animals, in Hawaii, in mainland USA and in Australia.

This paper shows that community wide cannabis exposure is linked to the incidence of body wall defects of each kind. The relationship satisfies the epidemiological criteria for being a causal relationship in nature – that is cannabis causes body wall birth defects.


How cannabis might do this is an important question for many reasons. Cannabis is known to be toxic to the genes which control how our bodies are made by dozens of mechanisms. However, it is worth considering two of the most important specifically.

When bodies are formed inside our mother’s womb they are controlled by a weaving process of special chemicals which guide body pattern formation, development and growth. These chemicals are called “morphogens” from the Greek meaning the “beginning of structure”. These morphogens form gradients (smooth increases in concentration) which closely specify in detail the type and placement of all the cells of our body. Cannabis messes up body morphogen gradient formation and the receptors which receive the signals. It does this both directly and by interfering with gene control mechanisms.

Gene control systems exist inside cells at many levels. They are generally referred to as the “epigenome” from the Latin – “upon or after the genes”. The epigenetic signals control which genes are turned on and where and when. This process is obviously vitally important inside the developing baby. Cannabis interferes with this process for muscles, for blood vessels which form the framework for the developing body wall, and for the body wall itself, so this becomes a second important general pathway by which cannabis can cause body wall defects.


Importantly epigenomic mechanisms can be inherited for several generations – at present we think at least 3 or 4 generations, so this issue passes down to subsequent generations, and can skip 1 or 2 generations.

All of these mechanistic insights and understandings help us to appreciate how cannabis causes body wall birth defects in many animal species and human populations across the world.

Cannabis also causes many other birth defects by these and other mechanisms. Cannabis genotoxicity and epigenotoxicity has also been linked with the development of many cancers. Cannabis genotoxicity and epigenotoxicity has also been shown to powerfully increase the rate of aging of our bodies, an effect which becomes much worse as we age.

All of these issues mean that cannabis exposure in human populations should be tightly controlled in the same way that we do for all other known important genotoxins which damage genes and epigenome multi-generationally.

Full article title: European Epidemiological Patterns of Cannabis- and Substance-Related Body Wall Congenital Anomalies: Geospatiotemporal and Causal Inferential Study

Authors: Dr. Stuart Reece, Gary Kenneth Hulse


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