A nurse is assisting with the care of a client who is at 37 weeks of gestation and has placenta previa. Which of the following risks is the primary rationale the nurse should avoid performing a pelvic examination?

Choice A rationale:
Fetal head compression is unlikely to cause variable decelerations in the fetal heart rate. During contractions and labor, the fetal head may experience pressure, but this usually leads to early decelerations, not variable decelerations. Early decelerations are considered benign and are caused by the head's pressure stimulating the vagus nerve, resulting in a temporary decrease in heart rate.
Choice B rationale:
Umbilical cord compression is a known cause of variable decelerations in the fetal heart rate. When the umbilical cord is compressed, it can temporarily disrupt blood flow and oxygen supply to the fetus, leading to decelerations. Variable decelerations often appear as abrupt, sharp drops in the fetal heart rate and are typically characterized by their unpredictable
nature.
Choice C rationale:
Maternal opioid administration is not a direct cause of variable decelerations in the fetal heart rate. While opioids can cross the placenta and may affect the fetus, they are more likely to cause other issues, such as respiratory depression in the newborn, rather than variable decelerations.
Choice D rationale:
Uteroplacental insufficiency is not the primary factor causing variable decelerations. Uteroplacental insufficiency refers to an inadequate blood flow and oxygen delivery to the placenta, which can lead to late decelerations in the fetal heart rate, not variable decelerations.

Choice A rationale:

The umbilical cord typically contains two arteries and one vein. Arteries carry oxygen-depleted blood and waste products from the fetus to the placenta for removal, while the vein carries oxygenated blood and nutrients from the placenta to the fetus. This arrangement is essential for maintaining proper fetal circulation during pregnancy.

Choice B rationale:

This choice is incorrect because the umbilical cord usually contains two arteries and one vein, not just one artery and one vein. Having only one artery could indicate a potential vascular abnormality or congenital issue that may require further investigation or medical attention.

Choice C rationale:

This is the correct answer. The umbilical cord usually contains two arteries and one vein. The presence of two arteries allows for the efficient removal of waste products and carbon dioxide from the fetus, while the single vein delivers essential nutrients and oxygen to support the baby's growth and development.

Choice D rationale:

This choice is incorrect as it states two veins and one artery, which is not the typical configuration of blood vessels in the umbilical cord. Having two veins and one artery would disrupt fetal circulation and hinder proper nutrient and waste exchange between the fetus and the placenta.