What is the most appropriate statement from the nurse when coaching the laboring woman with a fully dilated cervix to push?

Choice A rationale Pushing between contractions is ineffective because the uterine muscle is relaxed and not applying maximal downward force to the fetus. Pushing should coincide with the peak of the contraction when the uterus provides the maximal, coordinated expulsive force. Choice B rationale The most appropriate technique is to use open-glottis pushing during a contraction. The woman is encouraged to take a deep breath at the contraction's start and push with the second exhalation (not holding the breath) for about 6-8 seconds, which allows oxygen exchange and avoids excessive pressure (Valsalva maneuver) that can decrease oxygenation. Choice C rationale Pushing continuously for the duration of the contraction is often too long and can lead to the Valsalva maneuver (holding breath and straining), which significantly raises intrathoracic pressure. This can compromise venous return to the heart, reduce cardiac output, and potentially decrease uteroplacental perfusion and fetal oxygenation. Choice D rationale The instruction to hold your breath and push for 10 seconds describes the traditional, but now discouraged, closed-glottis (Valsalva) pushing method. This practice can cause rapid maternal fatigue and significantly reduce blood flow to the placenta, leading to fetal compromise due to decreased oxygen supply.