Endocannabinoid System in Pregnancy Maintenance and Labor: A Mini-Review

Abstract

The endocannabinoid system (ECS) is a cell-signaling system present in multiple organ systems and is an integral part of sustaining the microenvironment necessary for early pregnancy success and maintenance. It plays a significant role in embryo development, transport and implantation as well as placentation. The current theory behind the initiation of term labor is that it is a complex, multifactorial process involving sex steroid hormones, prostaglandin production and interplay at the maternal-fetal interface resulting in increased expression of receptors and gap junctions that promote uterine activation. There is increasing evidence that, in addition to early pregnancy events, the ECS plays a regulatory role in pregnancy maintenance and the timing of labor. This review presents an overview of the ECS in pregnancy that focuses on late gestation and parturition.

Keywords: anandamide; cannabinoid receptor; endocannabinoid system; labor; myometrium; parturition; pregnancy; preterm labor.

Figure 1

Maternal plasma anandamide levels as described by Habayeb and colleagues (14) relative to levels of progesterone and estrogens during pregnancy. (Figure including levels of progesterone and estrogens published in Boron WF, Boulpaep EL: Medical Physiology, 3^rd ed. Philadelphia, Elsevier, 2017. Data from Wilson JD, Foster DW, Kroenber M, Larsen PR: Williams Textbook of Endocrinology, 9^th ed. Philadelphia, WB Saunders, 1998. Used with permission.)