Comparing the effects of Carbetocin and Oxytocin on pregnant uterine muscle with and without prior Oxytocin treatment

In vitro contractions produced by oxytocin were significantly higher than those from carbetocin in human myometrium.

• The motility index of contractions induced by oxytocin was higher than that of carbetocin in both control and oxytocin-pretreated groups.
• For control groups, the regression-estimated difference in motility index was 0.857 (95% CI, 0.290 to 1.425; P = 0.003).
• In oxytocin-pretreated groups, the motility index difference was 0.813 (95% CI, 0.328 to 1.299; P = 0.001).
• Oxytocin pretreatment significantly lowered the motility index for both oxytocin and carbetocin compared to their respective controls.
• The reduction in motility index for oxytocin was -1.040 (95% CI, -1.998 to -0.082; P = 0.03), and for carbetocin it was -0.996 (95% CI, -1.392 to -0.560; P < 0.001).

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