There was a positive correlation between the tenderness of the uterus before labour and CB1 and CB1a expression. This symptom could be associated with worsened contractions of the uterus. In earlier studies, the stimulation of the CB receptor led to the relaxation of the skeletal muscles[37, 38], smooth muscles of blood vessels[39], and uterine smooth muscles[40]. Therefore, the stimulation of the CB receptors in the uterus was described as tocolysis[41]. As a result, a decrease in level of the receptors could lead to preterm uterine contractions and PTB. CB1 and CB1a expression was not connected with PTB. Nevertheless, in the study group, lower CB1 and CB1a expression correlated with higher uterine pain. This correlation could be caused by the generally increased pain feeling of the patients. Stimulating the peripheral CB receptors could lead to an antipoint effect without central, psychoactive action[42–44], also in the uterus[34]. There are no studies describing supervised usage and the influence of selective CB modulators in pregnant women. However, retrospective studies of exogenous cannabinoid usage confirmed a rising percentage of adverse pregnancy outcomes[45–47]. What if there were selective CB stimulators without harmful effects? They could be used to relieve patients’ pain without the psychoactive influence of the cannabinoids. The potential role of CB2 expression in human myometrium in the development of the placenta, uterus, and thus in childbirth, was demonstrated by Dennedy[40]. Further studies gave information about an important role of anandamide in supporting pregnancy, including in placental hormonal activities and its development[48, 49]. Studies also suggest that testing for anandamide levels may be one methods used to predict PTB[50].