
A new review of evidence of Researchers from Oregon Health & Science University suggests that the use of cannabis while pregnancy increases the risk of negative health results for the baby. (Getty Images)
A systematic update review reveals that cannabis consumption during pregnancy seems to increase the chances of premature birth, low birth weight and infant death.
The study of researchers from Oregon Health & Science University published today in the journal Jama Pediatrics.
The main author is a doctor-scientist who provides prenatal care for high-risk pregnancies at the OHSU.

Jamie Lo, MD, MCR (Ohsu)
“The patients come to me during their prenatal visits saying:” I stop smoking and drinking, but is it sure to still use cannabis? ” “Said the main author Jamie Lo, MD, MCRAssociate professor of obstetrics and gynecology (maternal-fetal medicine) at the Ohsu Medicine School. “Until direct damage has been proven, they perceive that he is sure to use.”
In fact, cannabis remains one of the most common substances used during pregnancy which is still illegal under federal law, and, unlike the decreases in prenatal alcohol or nicotine consumption, cannabis consumption is increase. LO said many of his patients hesitate to abandon cannabis during pregnancy, as it helps reduce current prenatal symptoms such as nausea, insomnia and pain.
Researchers have updated the systematic review and meta-analysis, based on a total of 51 observation studies involving 21.1 million people to examine the potential adverse effects of cannabis consumption during pregnancy. The researchers have found eight new studies since their previous update, increasing the certainty of evidence of “very low to low” to “moderate” for increased chances of low birth weight, premature births and babies being weak for their gestational age.
The updated examination has also indicated increased chances of mortality to the newborn, but still with low certainty.
Researchers noted that the new systematic review includes a greater proportion of human observation studies examining people who only use cannabis, but also do not use nicotine. And even if the evidence is low to moderate for unwanted results, LO noted that the results are consistent with final evidence in non -human primates exposed to THC, the main psychoactive compound of cannabis.
Related research on animal models included a standard prenatal ultrasound and MRI imaging which revealed a harmful effect on the placenta, in terms of blood flow and oxygen availability in addition to a decrease in the volume of amniotic fluid.
“These results tell me as obstetricians that the placenta does not work as it would normally during pregnancy,” said LO. “When the placenta does not work well, it can affect the development and growth of the baby.”
Even if cannabis remains a substance of appendix 1 under the federal law on controlled substances, Oregon is one of the many states which have legalized it under the law of the State for medicinal and recreational purposes. LO said that it recommends a damage reduction approach to patients. For those who cannot refrain, she advises them to reduce the quantity and frequency of use to help reduce the risk of prenatal and infant complications.
“Even using less can mitigate the risk,” she said. “Abstinence is ideal, but it is not realistic for many patients.”
In addition to LO, co-authors include Snehapriya Yeddala, pharmd.,, Beth Shaw, ms,, Shannon Robalino, msof Ohsu; Chelsea Ayers, MPH,, Rachel Ward, Bathe veterans’ health care system; And Devan Kansagara, MDfrom Ohsu and Portland VA.
Research is part of the evidence of evidence on the Marijuana Project (STEM), funded by the Rural Health Office in the Health Administration of Veterans of the US Affairs Department. Research is also supported by the National Institute on Drugs Abuse of the National Institutes of Health, Award DP1 DA056493. The content is only the responsibility of the authors and does not necessarily represent the official views of the AV or the NIH.