Maternal Characteristics Associated With Preconception Marijuana Use

Over the last 25 years, illicit cannabis use and cannabis use disorders have increased among US adults, and 28 states have passed medical marijuana laws (MML). Little is known about MML and adult illicit cannabis use or cannabis use disorders considered over time.

Objective To assess the effects of use of cannabis during pregnancy on maternal and fetal outcomes. Data sources 7 electronic databases were searched from inception to 1 April 2014. Studies that investigated the effects of use of cannabis during pregnancy on maternal and fetal outcomes were included. Study selection Case–control studies, cross-sectional and cohort studies were included. Data extraction and synthesis Data synthesis was undertaken via systematic review and meta-analysis of available evidence. All review stages were conducted independently by 2 reviewers. Main outcomes and measures Maternal, fetal and neonatal outcomes up to 6 weeks postpartum after exposure to cannabis. Meta-analyses were conducted on variables that had 3 or more studies that measured an outcome in a consistent manner. Outcomes for which meta-analyses were conducted included: anaemia, birth weight, low birth weight, neonatal length, placement in the neonatal intensive care unit, gestational age, head circumference and preterm birth. Results 24 studies were included in the review. Results of the meta-analysis demonstrated that women who used cannabis during pregnancy had an increase in the odds of anaemia (pooled OR (pOR)=1.36: 95% CI 1.10 to 1.69) compared with women who did not use cannabis during pregnancy. Infants exposed to cannabis in utero had a decrease in birth weight (low birth weight pOR=1.77: 95% CI 1.04 to 3.01; pooled mean difference (pMD) for birth weight=109.42 g: 38.72 to 180.12) compared with infants whose mothers did not use cannabis during pregnancy. Infants exposed to cannabis in utero were also more likely to need placement in the neonatal intensive care unit compared with infants whose mothers did not use cannabis during pregnancy (pOR=2.02: 1.27 to 3.21). Conclusions and relevance Use of cannabis during pregnancy may increase adverse outcomes for women and their neonates. As use of cannabis gains social acceptance, pregnant women and their medical providers could benefit from health education on potential adverse effects of use of cannabis during pregnancy.

Data System. The Pregnancy Risk Assessment Monitoring System (PRAMS) is an ongoing state-based surveillance system of maternal behaviors, attitudes, and experiences before, during, and shortly after pregnancy. PRAMS is conducted by the Centers for Disease Control and Prevention’s Division of Reproductive Health in collaboration with state health departments. Data Collection/Processing. Birth certificate records are used in each participating jurisdiction to select a sample representative of all women who delivered a live-born infant. PRAMS is a mixed-mode mail and telephone survey. Annual state sample sizes range from approximately 1000 to 3000 women. States stratify their sample by characteristics of public health interest such as maternal age, race/ethnicity, geographic area of residence, and infant birth weight. Data Analysis/Dissemination. States meeting established response rate thresholds are included in multistate analytic data sets available to researchers through a proposal submission process. In addition, estimates from selected indicators are available online. Public Health Implications. PRAMS provides state-based data for key maternal and child health indicators that can be tracked over time. Stratification by maternal characteristics allows for examinations of disparities over a wide range of health indicators.