Cannabis in pregnancy

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The effect of cannabis consumption on the fetus

The effect of the fetus’s exposure to cannabis is not sufficiently clear. Given that the use of cannabis is very common, it is necessary to evaluate the effect of pregnant women on the development of pregnancy and childbirth. It is important to note that women who consume cannabis often also smoke tobacco and consume alcohol and should therefore be taken into account.

Among cannabis users, feelings of pleasure, joy, euphoria, relaxation, pleasure, sensuality, and spirit are reported when consuming cannabis [1]. Negative effects are usually described as anxiety, panic and rarely a psychotic attack.

Social cannabis users report using leisure, relaxation, social activities, parties, funerals, listening to music, and watching movies.

In general, middle-class adults use cannabis for two main purposes: to improve concentration and relaxation. Compared to them, heavy users of cannabis tend to use it as an escape from their reality, they are usually poor and have lower socioeconomic status and tend to addictions [2] [3]. Young men (20-24) are more likely to develop dependence on cannabis although there is no increase in mortality [4].

There was no increased risk of congenital malformations in infants exposed to cannabis during pregnancy. The effect of exposure to cannabis in the uterus is not yet clear, although the common outcome is low birth weight.

A study of 7452 infants, including infants exposed only at the beginning of pregnancy, showed that infants exposed to cannabis smoke were 277 grams lower on average than infants who were not exposed to cannabis during pregnancy. Babies exposed only at the beginning of pregnancy and not later were only 156 grams lower than the average weight of infants not exposed to cannabis [5].

Similarly, another study found in 1690 infants that the average birth weight was 139 grams lower for infants exposed to cannabis three times a week or more [6]. In addition, a third study found a twofold lower risk of birth weight than infants not exposed to cannabis, but only in European and American mothers and not of mothers of different ethnic origin. The analysis found that the weight was lower by 131 grams on average.

Most studies of mothers ‘exposure to cannabis have been reported in mothers’ reports.

Other differences found in infants for mothers consuming cannabis were height differences (0.5 cm less than infants of mothers who did not consume cannabis) and smaller head circumference, although their brains were no smaller. [8] Slightly smaller. [9] Since these findings were also found in women who consume tobacco, smoking, it can be assumed that it is not cannabis that makes the difference, because they may have smoked tobacco along with cannabis.

IgG tests of infants in their first two days showed a change in sleep patterns between infants born to mothers who consumed cannabis and mothers who did not consume [10].

THC easily passes the placenta [11], [12] and is associated with intrauterine growth retardation and low birth weight. In addition, there are studies [13], [14] which show that fetal exposure to cannabis during pregnancy is more related to psychiatric illnesses (schizophrenia).

The human body has an endocannabinoid system that supports the immune system and makes feedback of neurotransmitters. During pregnancy, the distribution and levels of endocannabinoids are different than in adults. Levels of endocannabinoids AEA and AG2 * vary in the fetus during pregnancy. AG2 At the peak during fetal development, AEA plays a role at the beginning of pregnancy in implantation in the womb and towards the end of pregnancy, its level rises again [15].

The findings from the few studies in laboratory mice and humans indicate significant molecular changes in the neurophysiological development of the fetus. There is no doubt that there is room for caution and further research on the subject.

CONCLUSIONS: Care should be taken with caution and considerations between cannabis consumption and prescription drugs, sometimes cannabis is preferred and sometimes not. Consumption, frequency of consumption, and species (in terms of THC-rich or CBD-rich species) seem to be important. The findings are particularly relevant in view of the growing popularity of cannabis consumption in young mothers, who prefer cannabis over other prenatal drugs for various reasons, along with the increased potency of cannabis strains today.

*AEA= Anandamide

* 2-AG =2-Arachidonoylglycerol

*THC= Δ9-Tetrahydrocannabinol

*CBD= Cannabidiol


Eur Child Adolesc Psychiatry. 2014 Oct; 23(10): 931–941. Published online 2014 May 3. doi:  10.1007/s00787-014-0550-y

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