A woman who had two previous cesarean births is in active labor, when she suddenly complains of pain ...

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Pain between the scapulae may occur when the uterus ruptures because blood accumulates under the diaphragm. This is an emergency that requires medical intervention.
Repositioning the woman with her hips slightly elevated is the treatment for a prolapsed cord. That position in this scenario would cause respiratory difficulties.
Observing for high uterine resting tones should have been done before the sudden pain. High uterine resting tones put the woman at high risk for uterine rupture.
The woman is now at high risk for shock. Nonadditive intravenous fluids should be in-creased.