Final answer:
A decrease or loss of fetal heart rate (FHR) variability can be caused by severe contractions, oxygen deprivation, electrolyte imbalances, and other conditions leading to fetal distress, potentially necessitating an emergency Caesarian section.
Step-by-step explanation:
The decrease or loss of FHR variability can be caused by a number of factors including, but not limited to, severe contractions that limit oxygenated blood flow to the fetus, leading to fetal distress.
Conditions such as hypoxia, acidosis, alkalosis, electrolyte imbalances like altered sodium and potassium levels, and hypothermia can also influence heart rate variability.
It's important for medical professionals to intervene when such decreases are observed as they might signal the need for emergency delivery methods such as vacuum, forceps, or a Caesarian section to prevent complications.
Regarding interventions, the treatment will depend on the underlying cause of the decrease in heart rate variability. These can range from providing supplemental oxygen, managing electrolyte imbalances, and adjusting any drugs that might be affecting the heart rate, such as beta blockers.
In some cases, like with severe hypothermia or during open heart surgery, a patient might be connected to an artificial heart-lung machine to maintain circulation and gas exchange.