Final answer:
The cascade of BPP loss due to hypoxemia typically starts with reduced fetal heart rate variability, followed by cessation of fetal breathing movements, decreased fetal body movements, and reduced amniotic fluid volume.
Step-by-step explanation:
The typical cascade of loss of biophysical profile (BPP) parameters associated with hypoxemia starts with a decrease in fetal heart rate variability, which is often the first sign of fetal distress. Prolonged and powerful contractions can impede oxygenated blood flow to the fetus, making it critical for periods of relaxation to occur between contractions to restore blood flow and prevent distress. As hypoxemia progresses, fetal breathing movements may cease due to the high levels of carbon dioxide in the fetus's blood causing acidosis, which can trigger the respiratory center in the brain. Moreover, hypoxemia can lead to a decrease in fetal body movements and eventual reduction in amniotic fluid volume.