Final answer:
Fetal scalp blood sampling is used during labor to assess fetal well-being, especially if there are indications of fetal distress, by measuring fetal blood pH and lactate levels.
Step-by-step explanation:
Fetal scalp blood sampling may be warranted in situations where there is a need to assess the wellbeing of the fetus during labor, particularly if there is concern about fetal distress. This procedure allows for the measurement of fetal blood pH and lactate levels, which can give insight into the fetal oxygenation status. It is usually considered when there are abnormal fetal heart rate patterns or other indications of possible compromised fetal oxygen supply during labor. Monitoring fetal well-being is crucial as fetal distress can lead to interventions such as emergency cesarean delivery to prevent adverse outcomes.