Even less frequent cannabis use during pregnancy may impact fetal growth significantly: Study

As more people use cannabis for recreational purposes, attitudes towards the drug have changed. For example, research has shown that dispensaries often recommend cannabis - also referred to as marijuana - to pregnant women to ease pregnancy symptoms, especially morning sickness.

“We show that even when marijuana use occurred only in the first trimester of pregnancy, birth weight was significant reduced, by more than 150g on average,” said Dr Beth Bailey, a senior author of the study published in Frontiers in Pediatrics. “If that use continued into the second trimester, newborn head circumference was significantly decreased as well.”

“These findings are important as newborn size is one of the strongest predictors of later child health and development,” added Dr Phoebe Dodge, the study’s first author.

The effects the scientists observed have also shed light on patterns of use. Their study showed that occasional use, such as for first trimester morning sickness, may reduce fetal growth in the same way as continued use throughout pregnancy. The same is true for other use in early stages, including cases when someone uses cannabis not knowing they are pregnant.

“The best recommendation is that women should be advised to quit marijuana use prior to becoming pregnant,” Dodge said.

Reference:

The Impact of Timing of In Utero Marijuana Exposure on Fetal Growth, Frontiers in Pediatrics, DOI 10.3389/fped.2023.1103749