Impact on the health of newborns from marijuana use during pregnancy

The legalization of marijuana in many places around the world ensures that the risk of harm to users is reduced. However, there is not enough evidence to understand the effect of marijuana when used by pregnant women.

Study: Effects and quantities of marijuana use in relation to neonatal outcomes. Image Credit: Tatiana Tomsikova / Shutterstock

In a recent study published in Phytomedicin PlusIn this study, researchers evaluated the effect of marijuana use on neonatal outcomes.

about studying

In this study, researchers evaluated the effects of marijuana use by expectant mothers on newborn outcomes.

The team performed a literature search using the keywords “marijuana,” “cannabis,” “prenatal,” “postnatal,” “newborn,” and “impact,” or “impact,” in the Web of Science Core Collection database. Records included in the study were managed and analyzed using the scientific aggregation method. The team then put together a timeline of the most cited literature between 2012 and 2022.

A revision of the International Classification of Diseases (ICD) codes was also performed for cannabis-cannabis and neonatal effects by entering the search terms ‘fetal’, ‘newborn’ and ‘cannabis’ into the ICD-11 coding tool for mortality and morbidity statistics (MMS). The team also analyzed the bioactivity of the main cannabinoids, namely cannabinoids (CBC), cannabigryl (CBG), cannabinol (CBN), and delta-9-tetrahydrocannabinol (THC) found in marijuana by performing the assay in silico.


The study included a total of 4,466 reviewed publications, of which 857 constituted 12 groups of highly cited journal papers on a similar topic. The 12 groups included medical marijuana law, preventative behavioral strategies, medical marijuana, adolescent marijuana user, brain structure, young adult, legalization of recreational marijuana, birth outcomes, marijuana dependence, adverse outcomes, cohort study, and medical marijuana.

The team found that the number of pregnant women using marijuana increased from 2.37% in 2002 to 3.85% in 2014. Approximately 48% to 60% of marijuana users continue to use marijuana even during pregnancy. The team noted that the number of hospital admissions for a mother for marijuana use increased by 23% within three years after the introduction of recreational marijuana (RML) laws in the United States.

The reviewed literature showed that marijuana can cross the placenta, which can lead to several adverse effects on the infant. It can also affect the neurological development of the fetus as well as perinatal outcomes. Furthermore, women who used marijuana during pregnancy had higher chances of developing anemia, while their babies had a lower birth weight. It was found that marijuana also affects the normal transmission and condition of the placenta throughout pregnancy. Furthermore, short-term exposure to cannabidiol (CBD) can increase the permeability of the placental barrier towards pharmacological agents, which may increase fetal risks.

The team also noted that marijuana use during pregnancy increased the resistance index as well as the uterine artery pulsation index, which may increase placental resistance and reduce placental circulation. Moreover, the concentration of carbon monoxide in the blood is five times higher in pregnant women who use marijuana than in those who use tobacco. This can lead to impaired respiratory gas exchange in the mother, resulting in multiple adverse effects on the fetus.

Furthermore, intrauterine exposure to marijuana can impair cognitive function as well as increase sensitivity to drug abuse in the infant. Also, fetal exposure to cannabis can increase the brain’s sensitivity to the effects of ethanol on apoptosis. Studies have also shown that children exposed to marijuana in the womb have problems with visual acuity, visual motor coordination, and visual analysis.

At week 14 of gestation, cannabinoid receptor type 1 is present in the central nervous system of the human fetus, with receptor density increasing with pregnancy. This indicates that endocannabinoids play an important role in human brain development. The endocannabinoid system (ECS) includes these receptors and was thus important in the early stages of neuronal development. Since marijuana passes freely through the placenta into breast milk, it can spread to the fetus as well. The role of cannabis in implantation of the pregnancy and placenta placement as well as the neurological development of the fetus indicates that marijuana is dangerous for the development of the fetus in general.


Overall, the results of the study showed multiple negative effects of marijuana use by pregnant women on their offspring. However, the overall effects of marijuana on neonatal outcomes remain inconclusive due to the involvement of various economic, social, and political factors. Researchers believe that stopping marijuana use during pregnancy can reduce the risks and lead to the highest level of safety for mother and child.


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