The student nurse is preparing to assess the fetal heart rate (FHR). She has determined that the fetal back is located toward the client's left side, the small parts toward the right side, and there is a vertex (occiput) presentation. The student nurse should initially begin auscultation of the fetal heart rate in the mother's:

A) Check fetal heart rate:
The first priority when a woman's membranes spontaneously rupture is to assess fetal well-being. The nurse should immediately check the fetal heart rate (FHR) after the rupture of membranes to evaluate for any signs of fetal distress. If there are any concerns regarding the FHR, further interventions may be needed, such as adjusting the maternal position or preparing for a possible emergent delivery. Monitoring the FHR will help guide subsequent decisions regarding care.

B) Instruct her to bear down with the next contraction:
While the second stage of labor involves pushing, it is important to wait for the appropriate signs of readiness before instructing the mother to bear down. The nurse should ensure the cervix is fully dilated and that fetal descent is progressing appropriately. Rushing into pushing too early or without proper readiness can lead to maternal and fetal complications.

C) Place her legs in stirrups:
Placing the mother’s legs in stirrups is typically done once she is in the active phase of pushing (typically when the cervix is fully dilated and fetal descent is ready). It is not the first priority immediately after the membranes rupture. The nurse should first assess the fetal heart rate and ensure the woman is comfortable and ready to push before assuming the lithotomy position or placing her legs in stirrups.

D) Test a sample of the amniotic fluid for meconium:
Testing the amniotic fluid for meconium should be done if there is concern that the amniotic fluid may be stained, as meconium in the amniotic fluid can be a sign of fetal distress. However, the first action after the membranes rupture is to check the fetal heart rate. If the FHR is normal, further actions, like testing the fluid, may follow, but the priority remains assessing fetal well-being.

A) Decrease the client's IV fluids:
Sinusoidal fetal heart rate patterns are concerning and typically indicate severe fetal distress, which is often associated with conditions such as fetal anemia, hypoxia, or central nervous system (CNS) damage. Decreasing IV fluids is not an appropriate response to a sinusoidal pattern. The primary focus should be on fetal well-being, not fluid management, in this situation.

B) Prepare the client for an emergent birth:
This pattern is typically associated with severe fetal compromise and is an ominous sign. Immediate intervention is required, and emergent delivery may be necessary to prevent further fetal distress and potential harm. The nurse should promptly notify the healthcare provider and prepare the client for an emergency cesarean delivery or other urgent interventions.

C) Turn the client to a supine position:
The supine position is not recommended for managing fetal distress, as it may decrease uterine blood flow and worsen the situation, especially if the fetus is experiencing hypoxia. The appropriate intervention for addressing a sinusoidal heart rate pattern is not repositioning the client in a supine position, but rather preparing for emergency delivery and providing immediate support to stabilize both mother and fetus.

D) Document the findings:
While it is important to document any fetal heart rate pattern, sinusoidal patterns require immediate action. Documentation alone is not sufficient in this case, as it does not address the potential life-threatening situation for the fetus. The nurse should not delay action, and the focus should be on preparing for emergency birth and notifying the healthcare provider immediately.