Prenatal cannabis use linked to adverse birth outcomes

Cannabis use in pregnancy is associated with preterm birth, small for gestational age, and low birth weight, a recent literature review has found. The study is significant in light of continued prenatal cannabis use. There are potential adverse effects on fetal and neonatal outcomes. But some pregnant women use it in particular to control nausea associated with pregnancy. A previous review found low confidence in the results; the current meta‐analysis now has moderate confidence. The researchers hope that their study will help inform public health policies and patient counseling. “We were able to increase our certainty for these outcomes because of the increased number of studies and patients, consistency of findings, and the finding of a dose‐response association,” the researchers concluded. “Our findings are also consistent with prior reviews of this topic, although some included studies that did not adjust for tobacco co‐use or other important confounders, and multiple publications have added to the body of evidence since that time. Our review also analyzes more clinically relevant outcomes than previous reviews. As prenatal cannabis use is a modifiable risk factor, clinical and public health efforts to reduce it have the potential to mitigate pregnancy and offspring morbidity and mortality.” Strengths of the study cited by the authors include the ability of clinicians to use the results to discuss prenatal cannabis use with pregnant patients or those trying to conceive. Other strengths were strict exclusion criteria and adjusted effect sizes to adjust for confounders. Limitations include lack of heterogeneity in the literature, and lack of information on the mode of delivery (smoking, edible), timing, frequency, potency, or duration of prenatal cannabis use. Significantly, the researchers were not able to adjust for confounding from severe nausea and vomiting during pregnancy, because this information was not included in the studies reviewed. Severe nausea and vomiting, not only can be a reason for cannabis use, but by themselves increase the risk for adverse outcomes, including fetal growth restriction, low birth weight, and preterm birth, the authors wrote. The study, “Prenatal cannabis use and neonatal outcomes: A systematic review and meta‐analysis,” was published online May 5 in JAMA Pediatrics .