Final answer:
c) Inhibit calcium influx into myometrial cells
CCBs delay labor by inhibiting calcium influx into myometrial cells, which decreases uterine contractility and delays onset of labor.
Step-by-step explanation:
Calcium channel blockers (CCBs) act to delay labor by inhibiting calcium influx into myometrial cells. This process decreases the contractility of the uterus, as calcium ions play a critical role in muscle contraction, including the uterine muscles.
By blocking calcium entry, CCBs reduce the strength and frequency of uterine contractions, which can delay the onset of labor. This mechanism is distinct from oxytocin, which stimulates uterine contractions, and prostaglandins, which enhance contraction strength.
Labor induction often involves the use of pitocin, a pharmaceutical version of oxytocin, to stimulate contractions when necessary.