Uterus smooth muscle contraction

Uterus smooth muscle contraction is the result of coordinated activation and contraction of myometrial smooth muscle cells, leading to rhythmic shortening of the uterus that is required for labor and delivery. The process is governed by changes in intracellular calcium concentration, membrane depolarization, and signaling through multiple receptors including the oxytocin and prostaglandin receptors. Drugs can either promote (oxytocin, prostaglandins) or inhibit (tocolytics) contraction depending on clinical needs. Regulation is complex, involving hormonal, neural, ionic, and mechanical cues, and is an important therapeutic focus for management of preterm labor, induction of labor, and prevention of uterine atony.

Other names

Myometrial contractionUterine contractionMyometrial activityLabor contractions

Oxytocin: Binds to oxytocin receptor → Gq signaling → phospholipase C activation → increased intracellular Ca²⁺ → contraction. Prostaglandins: Bind to G protein-coupled receptors → similar increase in Ca²⁺, PKA/PKC signaling → contraction. Calcium channel blockers: Inhibit influx of Ca²⁺, preventing contraction. Other tocolytics: Block action potentials, prostaglandin synthesis, or receptor activation.