• Posted November 16, 2023

Cannabis Use During Pregnancy Ups Risk of Premature Birth, Low Birth Weight Babies

THURSDAY, Nov. 16, 2023 (Healthday News) -- Using cannabis during pregnancy may not be as benign as some think, with a new review showing it raises the risk for both premature and low birth weight newborns.

In turn, that raised the chances of these infants winding up in a neonatal intensive care unit (NICU) for special care.

There was reassuring news in the analysis, published Nov. 16 in the journal Addiction: Exposure to cannabis while in the womb did not translate into a higher risk for birth defects, death within one year or death from SIDS (sudden infant death syndrome).

Some moms-to-be turn to weed for help with morning sickness or general malaise, but the researchers noted that may be a dangerous decision.

“The global increase in cannabis use among women of reproductive age also extends to pregnant women," said study first author Maryam Sorkhu, at the University of Toronto's Centre for Addiction and Mental Health.

"We know that THC, the main psychoactive constituent in cannabis, can cross the placenta from mother to fetus and bind to receptors in the fetal brain," Sorkhu said in a news release from the Society for the Study of Addiction. "Our study adds to that knowledge by showing that prenatal exposure to cannabis heightens the risk of several adverse birth outcomes.”

In their review, the investigators pooled the results of 57 published studies that involved a total of nearly 13 million infants, almost 103,000 of them exposed to cannabis.

Three different outcomes were measured: premature birth, low birth weight and admission to a NICU.

Twenty of the studies measured the association between cannabis exposure and the risk of preterm delivery. In these, the combined results showed that pregnant women using cannabis were over 1.5 times more likely to have a preterm delivery, compared with women not using cannabis during pregnancy.

Meanwhile, 18 of the studies measured the risk of low birth weight. There, investigators found that women using cannabis during pregnancy were more than twice as likely to have a low-birth-weight baby compared with women who didn't.

Last but not least, 10 of the studies measured the risk of needing NICU admission. In these, exposed newborns were more than twice as likely to require NICU admission as non-exposed newborns.

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

More information

Visit the U.S. Centers for Disease Control and Prevention for more on cannabis use during pregnancy.

SOURCE: Society for the Study of Addiction, news release, Nov. 2023