Study: Maternal Marijuana Use Not Independently Associated with Lower Infant Birthweight

London, United Kingdom: Cannabis smoking during pregnancy, absent concurrent tobacco smoking, is not associated with lower birthweight outcomes, according to data published in the Journal of Perinatal Medicine.

A team of investigators from Kings College in London assessed the association between the maternal use of tobacco and cannabis on infant birthweight and head circumference.

Researchers reported that self-reported tobacco smoking during pregnancy, as well as the combined use of tobacco and cannabis, was associated with reductions in birthweight and head circumference. By contrast, "cannabis use alone was not associated with a significant reduction in birthweight or head circumference."

The study’s finding is consistent with those of prior studies, including a meta-analysis which concluded, "Maternal marijuana use during pregnancy is not an independent risk factor for adverse neonatal outcomes after adjusting for confounding factors."

Full text of the study, "Maternal smoking and cannabis use during pregnancy and infant outcomes," appears in the Journal of Perinatal Medicine. Additional information is available in the NORML fact-sheet, and in the NORML report.