Hey there, time traveller!
This article was published 23/5/2018 – that’s before recreational cannabis was legal in Canada, so language and information in the article may be dated.
Dear Herb: Concerning young women using cannabis in successfully controlling anxiety disorder, what are the standards or concepts regarding becoming pregnant and or breast-feeding?
Have there been any known adverse effects documented or reported upon the woman or child? — Maternal Misgivings
Dear Maternal: This is a sensitive question, but I'll do my best to summarize what modern science knows about the topic of cannabis and pregnancy, and provide links so you can read the research on your own.
First, my usual caution: I'm not a doctor or a scientist of any kind, merely a humble cannabis columnist. If you're making decisions about cannabis use during pregnancy, please consult with your doctor first.
From a historical perspective, there's no doubt that cannabis has long been used for obstetric and gynecological purposes. In a 2002 historical review, Dr. Ethan Russo found humans have used cannabis for "menstrual irregularity, menorrhagia, dysmenorrhea, threatened abortion, hyperemesis gravidarum, childbirth, postpartum hemorrhage, toxemic seizures, dysuria, urinary frequency, urinary retention, gonorrhea, menopausal symptoms, decreased libido, and as a possible abortifacient."
Modern western medicine doesn't put much faith in ancient medicine, though. Recent research on cannabis and pregnancy is a lot like other medical research on the effects of cannabis on the human body: we simply don't have enough information to reach irrefutable verdicts. Given the delicate nature of pregnancy and child-bearing, you would be hard-pressed to find a doctor who says it's definitely safe to use cannabis while carrying or nursing a child.
As you might imagine, it's ethically impossible to do any kind of study where pregnant women are instructed to use cannabis. Modern studies on the subject tend to rely on prospective mothers' self-reported cannabis use rather than any objective measure, which makes it tricky to reach any precise conclusions.Advertisement
A 2016 systematic review of such research, published in the journal Obstetrics & Gynecology, identified 31 studies of acceptable quality from 1982 to 2015, encompassing 7,851 women who used cannabis while pregnant. The review found that "women using marijuana in pregnancy were at increased risk for low birth weight... and pre-term delivery." After adjusting for other factors such as tobacco use and various socio-economic indicators, though, that risk diminished.
"We found that maternal marijuana use during pregnancy is not an independent risk factor for low birth weight or pre-term delivery after adjusting for factors such as tobacco use," wrote the authors.
That finding doesn't mean marijuana use during pregnancy should be encouraged or condoned, the authors stated.
A more recent paper by the Canada Fetal Alcohol Spectrum Disorder Research Network found mixed and insufficient evidence regarding cannabis use in pregnancy, and warned that there is no known safe level of cannabis use for pregnant women.
"Until more is known about both the short- and long-term effects of cannabis use across the lifespan (e.g., effects on babies, children, adolescents and adults), it is safest to avoid cannabis use while pregnant, while breast-feeding and around children," the authors recommended.
The American College of Obstetricians and Gynecologist agrees. In its official opinion, "women who are pregnant or contemplating pregnancy should be encouraged to discontinue marijuana use." Even medicinal cannabis use should be stopped in favor of alternative therapies for which there are better pregnancy-specific safety data, the college advises.
In terms of breast-feeding, the college found insufficient data to evaluate the effects of marijuana use on infants during lactation and breastfeeding, and in the absence of such data, marijuana use is discouraged.
Finally, one of the most thorough reviews of the overall health effects of cannabis on humans — a massive report by the National Academies of Sciences, Engineering and Medicine — reached four conclusions:
Overall, Maternal Misgivings, I'd say the available scientific evidence suggests it's safest to keep cannabis and child-bearing separate.
Until next week, readers, keep conceiving of clever questions for me to answer!
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