The new: In our international cohort study, continued use of cannabis at 15 weeks of pregnancy was associated with significantly lower birthweight, head circumference, birth length, and gestational age at birth, as well as with more frequent severe neonatal morbidity or death.
Women were excluded from our analysis if their pregnancy ended earlier than 20 weeks (Supporting Information, figure).
The research nurse asked women about the duration and frequency of cannabis use from 3 months before until 15 weeks into their pregnancy.
Women were allocated to four categories: never used cannabis, used cannabis but quit before pregnancy, used cannabis but quit during early pregnancy (by 15 weeks), and continued to use cannabis at 15 weeks of pregnancy.
Anthropometric measurements (infant birthweight, head circumference, birth length) were recorded by research midwives within 72 hours of birth.
The association between duration of cannabis use during pregnancy and severe neonatal morbidity or death was evaluated by logistic regression.
Continued and high frequency of cannabis use during pregnancy were each associated with significantly poorer neonatal outcomes. »
