Opinion, Berkeley Blogs

Study: Mom’s pot use doesn’t hurt kids’ future grades?

By Tomás Aragón

For the last several weekends I saw the following advertisement (disclaimer: I am a lifelong subscriber and avid supporter of our local newspaper — the San Francisco Chronicle):

Of course, being the father of three children, the lower right corner caught my attention: “Study: Mom’s pot use doesn’t hurt kids’ future grades—Fears of maternal cannabis use are being overblown.”

Naturally, I wanted to read this health article published by Emily Earlenbaugh for GreenState.com. The article starts with the following in bold font:

“Is using pot during pregnancy safe? Well, compared to what? We know alcohol, tobacco and other drugs can cause birth defects and a whole host of other problems. By contrast, a new study suggests cannabis use during pregnancy does not cause lasting effects on child’s brain development.”

[NOTE (added June 2, 2018): Greenstate.com (SF Chronicle) removed the link above to the original article. They edited the article and and re-posted to this new link. Unfortunately, they removed all the original links to the cited study and to authoritative medical sites. The general message of the article is unchanged. To understand, continue reading. Thanks.]

To clarify the title, this article is actually about mom’s pot use during pregnancy citing a new study that “suggests cannabis use during pregnancy does not cause lasting effects on child’s brain development.” It is based on a one-page article from the UK that relied on a “huge amount of data of 6,018 families.” Here are the cannabis results from the study:

“While children of parents who had smoked tobacco or mothers who drank alcohol were more likely to have lower educational attainment than those who did not; parental cannabis use did not correlate with lower achievement. Still, researchers were careful to note that there were far fewer subjects in their study who used cannabis during pregnancy than those who used tobacco or alcohol.”

The UK study article is based on an observational (non-experimental) cohort study. The first question we ask for negative (no correlation) studies is, “Did the cannabis analysis have enough sample size and statistical power to evaluate the exposure-outcome relationship?” According to the study results only 2 percent of moms used pot during pregnancy. The investigators wrote, “Neither maternal nor paternal cannabis use was associated with educational attainment in observational analyses, but few mothers in our sample used cannabis regularly in pregnancy.” In other words, the study analysis was did not have a sufficient cannabis exposure sample size to test the cannabis question. There were no statistical power calculations. In fact, their conclusion does not even mention cannabis as a finding:

“Conclusion: The negative association in observational analysis between maternal smoking in pregnancy and child KS4 attainment is likely due to residual confounding rather than an intrauterine mechanism. Conversely, residual confounding may be masking a negative association between lower levels of alcohol drinking and KS4 attainment in observational analysis.”

The bottom line is that the UK study does not support Earlenbaugh’s claim that “Fears of maternal cannabis use are being overblown.”

Without question, Earlenbaugh leans toward approval of cannabis consumption by pregnant women (“I personally know several healthy babies whose mothers used cannabis throughout their pregnancy.”), or at least casting doubt on the authoritative recommendations (see below). The possible implication for non-pregnant readers might be, “If consuming cannabis is even safe for pregnant women and their babies (and their future kids’ grades!), surely it must be safe for me.”

To her credit, Earlenbaugh provides links to authoritative information; for example, to the National Academy of Sciences and Engineering’s report “The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research (2017)” and to the American College of Obstetricians and Gynecologists’ (ACOG) recommendations. Based on comprehensive reviews of existing scientific evidence, both recommend against any cannabis consumption during pregnancy.

Unfortunately, we know very little about the long-term, adverse health effects of cannabis consumption, especially with the new high-concentration formulations. In the absence of definitive scientific evidence, public health uses the Precautionary Principle:

“The principle implies that there is a social responsibility to protect the public from exposure to harm, when scientific investigation has found a plausible risk. These protections can be relaxed only if further scientific findings emerge that provide sound evidence that no harm will result.”

The Precautionary Principle absolutely applies to exposures during pregnancy. While there is still much to learn, all of us should advise pregnant women to not consume alcohol, tobacco, and cannabis products.

Why is this important to me? At a recent community health meeting a small-business cannabis entrepreneur announced with absolute confidence that cannabis is not only safe, but healthy, for pregnant women, their babies and their young children. He claimed it was based on “sound science.” I was very surprised. In retrospect, I guess I should not have been surprised.

What can you do for you or your family’s health? Always seek out authoritative information: your doctor, your local medical society, your local health department, your local school of public health. Advocate for more research on the health effects of the current formulations of cannabis, and for more community health education.