Background and Aims Postpartum hemorrhage (PPH) remains to be one of the leading causes of maternal morbidity and mortality attributed to the rising rate of uterine atony. Dexmedetomidine, a highly-selective alpha-2 agonist, has been used in obstetric practice due to its desirable effects. It has applications as an adjunct during neuraxial anesthesia, as well as in general anesthesia (GA) for caesarean delivery. Information on dexmedetomidine’s effect on the contractility of human myometrium remains limited.

Methods Term pregnant patients scheduled for elective CD under regional anesthesia were included. Myometrial tissues were collected by the obstetrician after the delivery of the fetus and placenta and were immediately placed in buffer solution and transferred to the laboratory. Tissue samples were divided into 3 strips and were mounted individually in organ bath chambers filled with physiological salt solution (PSS). Myometrial contractions recorded and were used for analysis as baseline equilibration contractions. The myometrial strips were pre-treated with oxytocin 10-5M for 2 hours and assigned to 3 groups: 1) Dex group (subjected to dose-response testing with increasing concentrations of dexmedetomidine10-9M to 10-4M), 2) Dex + Oxy group (received oxytocin at 20nM along with dexmedetomidine 10-9M to 10-4M), and 3) Control (only oxytocin 20nM).

Results There is a 363% increase in relative motility index recorded in the Dex group at 10-4M concentration. There is also an increase in relative MI in Dex

+ Oxy group however it was not significant (196%) owing to the desensitization phenomenon.

Conclusions Dexmedetomidine significantly caused an increase in myometrial contractility of pregnant human myometrium at 10-4M concentration.

Initial approval 22-0152-A