Predicting Preterm Labor by Measuring Endocannabinoids

A new diagnostic technique could help at-risk women
By Adrian Devitt-Lee On November 25, 2019
Pregnant woman of color in a black sports bra and boyshorts holding hands on her belly making a heart symbol.

The endocannabinoid system is increasingly recognized for its involvement in uterine function. Estrogen, for example, has been shown to regulate the expression of FAAH, the primary protein tasked with breaking down anandamide, the first endogenous cannabinoid compound identified in the mammalian brain.

Aberrant signaling by endocannabinoids and their molecular cousins, the prostaglandins, is implicated in menstrual pain and adenomyosis (heavy bleeding). New research from scientists in Italy, Britain, and Qatar adds to how we understand these conditions by probing the connection between endocannabinoid levels and preterm birth, meaning delivery before the 37th week of pregnancy.

The scientists measured the levels of FAAH and anandamide (AEA), along with two related lipids, called PEA and OEA, in 217 women at risk for preterm birth. Plasma AEA tends to increase during pregnancy until labor, so the researchers were hoping to find a threshold that could be used to predict preterm birth.

They found that an AEA concentration above 1.095 nanomolar (nM) was a useful predictor of preterm birth. The specificity (true negative rate) was 87%, meaning they will only miss about 1-in-10 cases using this threshold. On the other hand, the sensitivity (true positive) was only 26%, meaning 3-in-4 results are false positives.

The authors conclude that using anandamide as a marker was more accurate and less invasive than current testing methods. PEA could also be used as a marker for preterm birth, but FAAH and OEA levels were not well correlated.

Future research should replicate this diagnostic threshold prospectively.

Another recent study suggested that AEA levels are normally around 0.6-0.8 nM in the blood, but this fluctuates to some degree throughout the day. So, blood collection needs to be done in a consistent way.

Beyond pregnancy, altered AEA and PEA levels have also been proposed as a diagnostic marker for uterine cancer.


Based on this original article: “Prediction of preterm labour from a single blood test: The role of the endocannabinoid system in predicting preterm birth in high-risk women”


Adrian Devitt-Lee, Project CBD’s chief science writer, is pursuing a PhD in Mathematics at the University College of London.


Copyright, Project CBD. May not be reprinted without permission.

Revision date: 
Nov 25, 2019