CannaTrials adheres to evidence-based medicine – making statements based on medical evidence.

This page is excerpted and quoted from the National Academies of Science, Engineering, and Medicine.    A Committee of over 40 experts, researchers, and reviewers in The Health and Medicine Division published a 486 page report in 2017 entitled “The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research.
If you would like to access the entire report you may do so by clicking this link.

Medical Marijuana and Fetal Growth and Development

“Studies reviewed in Gunn et al. (2016) that examined the effect of cannabis exposure on birth weight reported both mean birth weights and the percentage of infants at low birth weight (LBW; defined as 2.2kg or 5.5 lbs). Gunn et al. (2016) found that in utero exposure to cannabis is associated with a decrease in birth weight among cannabis exposed infants (pOR, 1.77; 95% CI = 1.04–3.01; pooled mean difference  [pMD], −109.42 grams; 95% CI = −38.72 to −180.12) compared to those without cannabis exposure.

In their systematic review, Gunn et al. (2016) found that for the nine studies that reported neonatal length at birth (measured in centimeters), there was no statistically significant association between neonatal length and prenatal exposure to cannabis (pMD, −0.10; 95% CI = −0.65–0.45).

Gunn et al. (2016) found that among the 10 studies they reviewed that measured head circumference at birth, no statistical  association was found between cannabis exposure in utero and neonatal head circumference (cm) (pMD, −0.31; 95% CI = −0.74–0.13).

There are two ways to describe slower-than-expected growth for a particular duration of gestation. The first is intrauterine growth restriction (IUGR), an obstetric diagnosis based on serial ultrasounds during pregnancy. The second is small for gestational age (SGA), which applies to infants with a birth weight that is less than the 10th or 5th percentile on normative growth curves. The limitation of the latter is that it does not distinguish between those infants with true slow growth and those with normal growth in the lower percentiles.

In this category the committee considered infants who had malformations or anomalies diagnosed prenatally or after birth. Congenital malformations reflect abnormalities of fetal development in one or more organ systems and can occur throughout pregnancy. They may be identified before or after birth.

The findings for birth weight are consistent with the effects of noncannabinoid substances in smoked cannabis and cigarette smoking. It has been shown in several studies that the increases in carbon monoxide, with elevated carboxyhemoglobin blood levels, may be up to fivefold higher after marijuana than cigarettes (Wu et al., 1988). In other studies of marijuana exposure during pregnancy, the cause of the fetal growth restriction noted was proposed to be fetal hypoxia due to the shift in the oxyhemoglobin curve caused by carbon monoxide (Frank et al., 1990).

CONCLUSION 10-2 There is substantial evidence of a statistical association between maternal cannabis smoking and lower birth weight of the offspring. [1]

[1] The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research | The National Academies Press. 2017. Pages 249-253. Download the complete 486 page report.

**Important Note:  On many of the health conditions studied by NAS, there was no conclusive evidence of cannabis effectiveness from the study results they reviewed.  The authors included a long section on “research gaps.

It is the Vision and Mission of CannaTrials to fill in some of these research gaps with cannabis clinical trials using specific medical marijuana formulations and testing them in a research protocol with local patients, physicians, processors and dispensaries.  If you are interested in participating in a clinical trial, and helping improve scientific knowledge about health effects of cannabis, please click one of the buttons below on this page.

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