Consumption of marijuana or its derivatives during pregnancy can cause respiratory problems in babies, such as impaired breathing control and less sensitivity to carbon dioxide (CO two), factors that even favor the occurrence of sudden infant death. The alert is from a study published in the British Journal of Pharmacology.
The group of researchers from the São Paulo State University (Unesp) and the University of São Paulo (USP) administered a synthetic compound to pregnant rats with a brain action similar to that of the cannabinoids derived from marijuana. Most of the deleterious effects observed occurred mainly in male offspring.
“With the legalization and flexibility of marijuana and its derivatives in some countries and a considerable increase in consumption, pregnant women use these compounds present in the plant Cannabis sativa in the form of medication, due to its nausea-reducing properties, or even recreationally. However, the consequences of this exposure to cannabinoids in the fetus are still little known”, says Luis Gustavo Patrone, first author of the study conducted with support from FAPESP during his doctorate at the Faculty of Agricultural and Veterinary Sciences (FCAV-Unesp), in Jaboticabal.
Compared to rats that did not undergo intrauterine exposure to the substance, the exposed pups had a 29% higher neonatal mortality. In males, there was also an increase in shivering in the first days of life, due to abstinence, changes in basal breathing and in the ventilatory response to oxygen and CO two in addition to a lower capacity for expansion of the lungs.
The authors also observed a decrease in the efficiency of mitochondrial respiration in the brain, changes in the number of cannabinoid receptors (CB1) and catecholaminergic neurons in brain nuclei that control respiratory function. Together, these data reveal significant changes.
In females, more spontaneous apneic events (periods without breathing) occurred, in addition to reductions in serotonergic neuron populations in the brainstem. Together, these data reveal that intrauterine exposure to cannabinoids resulted in relevant changes in the mechanical and sensory control of ventilation, being more pronounced in males.
“Many cannabis compounds are known to easily cross the placenta and can interfere with endocannabinoid signaling pathways, which are produced by the brain itself. This can profoundly affect the neural and physiological functions of the fetus, including cardiorespiratory processes, causing long-lasting effects in postnatal life”, summarizes Luciane Gargaglioni, professor at FCAV-Unesp and coordinator of the study.
The work is part of a project also supported by FAPESP and coordinated by Gargaglioni.
Sudden death
The researchers point out that the use of marijuana during pregnancy may be associated with the occurrence of sudden infant death syndrome (SIDS), which is related to the detection of O gas concentrations two and CO two blood flow and ventilatory adjustments. Episodes of spontaneous apnea in females exposed to the substance during the study are indicators of the decrease in this control.
“If the pillow falls on the face and prevents breathing during sleep, for example, the baby who has this syndrome is not able to detect gas changes. While in a newborn with normal breathing control, this would wake him up and cry, in SIDS, even with large reductions in oxygen and increase in CO two the baby can die of suffocation”, explains Patrone.
Increased sensitivity to carbon dioxide was also tested, as it is a biological determinant of panic attacks. Males of different ages showed an exacerbated ventilatory response to CO two. Among females, the same pattern was observed only in juveniles.
“Prenatal exposure to cannabinoids, therefore, may increase sensitivity to carbon dioxide and, consequently, vulnerability to panic disorders,” says Gargaglioni.
The analyzes did not show significant changes in cardiovascular and body temperature control, at least in the short and medium term. The experiments were terminated when the animals completed 28 days of life.
“Although it is a study carried out in rats, it points to important changes in respiratory physiology as a result of exposure to cannabinoids in the womb and, therefore, issues a note of caution for the therapeutic or recreational use of cannabinoids by pregnant women”, concludes Patrone .
The article “Sex- and age-specific respiratory alterations induced by prenatal exposure to the cannabinoid receptor agonist WIN 55,212-2 in rats” 2 on Mice”) can be accessed here.