Prenatal cannabis exposure increases risk of adverse birth outcomes, study finds

Babies exposed to prenatal marijuana use are more likely to be born prematurely, have lower birth weights and require neonatal intensive care unit (NICU) care, according to a study published today in the journal Scientific Reports. anurati. However, marijuana-exposed infants were not at greater risk of birth defects or death within one year, including sudden unexpected infant death.

The global increase in cannabis use among women of reproductive age extends to pregnant women. We know that THC, the main psychoactive ingredient in marijuana, can cross the placenta from mother to fetus and bind to receptors in the fetus’s brain. Our study adds to the body of knowledge showing that prenatal exposure to marijuana increases the risk of several adverse birth outcomes.”

Microsoft. Mariam Sorkhu, first author

This meta-analysis (a synthesis of past studies) combined the results of 57 prior studies with a total of 12,901,376 child participants, of whom 102,835 were exposed to marijuana.

Twenty studies have measured the relationship between prenatal marijuana exposure and the risk of preterm birth. Among these, the combined results showed that mothers who used cannabis during pregnancy were one and a half times more likely to have a preterm delivery than mothers who did not use cannabis.

Eighteen studies measured the risk of low birth weight. Among these, the combined results showed that mothers who used marijuana during pregnancy were more than twice as likely to have low birth weight babies as mothers who did not use marijuana during pregnancy.

Ten studies measured the risk of needing NICU admission. Among these, the combined results showed that neonates exposed to intrauterine marijuana were more than twice as likely to require NICU admission as unexposed neonates.

The studies included in this meta-analysis were published between 1984 and 2023 in a wide range of countries.