Background: Research on prenatal cannabis use and adverse infant outcomes is inconsistent, and findings vary by frequency of use or cigarette use. We assess (1) the prevalence of high frequency (≥once/week), low frequency (<once/week), and any cannabis use during pregnancy by maternal characteristics and adverse infant outcomes; (2) the prevalence of infant outcomes by cannabis use frequency, stratified by cigarette smoking; and (3) the association between cannabis use frequency and infant outcomes, stratified by cigarette smoking.
Methods: Cross-sectional data from 8 states' 2017 Pregnancy Risk Assessment Monitoring System (n = 5548) were analyzed. We calculated adjusted prevalence ratios (aPR) between cannabis use frequency and infant outcomes with Modified Poisson regression.
Results: Approximately 1.7 % and 2.6 % of women reported low and high frequency prenatal cannabis use, respectively. Prevalence of use was higher among women with small-for-gestational age (SGA) (10.2 %) and low birthweight (9.7 %) deliveries, and cigarette use during pregnancy (21.2 %). Among cigarette smokers (aPR: 1.8; 95 % CI: 1.1-3.0) and non-smokers (aPR: 2.1; 95 % CI: 1.1-3.9), high frequency cannabis use doubled the risk of low birthweight delivery but did not increase preterm or SGA risk. Regardless of cigarette use, low frequency cannabis use did not significantly increase infant outcome risk.
Conclusions: Prenatal cannabis use was more common among women who smoked cigarettes during pregnancy. High frequency cannabis use was associated with low birthweight delivery, regardless of cigarette use. Healthcare providers can implement recommended substance use screening and provide evidence-based counseling and cessation services to help pregnant women avoid tobacco and cannabis use.
Keywords: Cannabis; Low birthweight; Maternal; Prenatal; Preterm birth; Small for gestational age.
Published by Elsevier B.V.