The grass isn’t always greener: The effects of cannabis on embryological development

ABSTRACT

Background

It has long been established that smoking tobacco during pregnancy causes increased risk of miscarriage, increased placental problems, reduction of birth weight, and a variety of birth defects [1].

In light of the recent legalization of marijuana in Colorado, Washington, Alaska and Washington, D.C., we felt it important to establish and publicize the causative relationship between cannabis usage and embryological outcomes. The main psychoactive cannabinoid in marijuana is delta-9-tetrahydrocannabinol (THC), which has a half-life of approximately 8 days in fat deposits and can be detected in blood for up to 30 days before becoming entirely eliminated from the blood [2]. These characteristics act as a direct risk factor to the developing embryo, as the maternal tissues act as reservoirs for THC and other cannabinoids.

Certain drugs cross the placenta to reach the embryo in the same manner as oxygen and other nutrients [3]. Drugs consumed during pregnancy can act directly on the embryo, or they can alter placental function, which is critical for normal growth and development.

Ingestion of drugs can interfere with these functions, resulting in compromised fetal development and growth [3]. THC readily crosses the placenta, which, in conjunction with slow fetal clearance, results in prolonged fetal exposure to THC, even after consumption is discontinued [2].

The use of marijuana in early pregnancy is associated with many of the same risks as tobacco, including miscarriage, congenital malformations, and learning disabilities [4]. Adverse effects of marijuana use during pregnancy have been exacerbated over the years, as THC levels in marijuana have increased nearly 25-fold since 1970 [5]. This paper looks to examine recent studies on cannabinoids and embryonic development in order to establish the mechanisms through which these cannabinoids act.

Source:  Friedrich, Joseph et al. “The Grass Isn’t Always Greener: The Effects of Cannabis on Embryological Development.” BMC Pharmacology & Toxicology 17 (2016): 45. PMC. Web. 21 Apr. 2017.

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