What does "marked variability" in fetal heart rate indicate?

Marked variability in fetal heart rate is characterized by an amplitude range of more than 25 beats per minute. This significant fluctuation in the fetal heart rate can be a reassuring sign that the fetus is well-oxygenated and that there are no major issues with fetal well-being. In many cases, marked variability is associated with the active state of the fetus, reflecting its ability to respond to stimuli and maintaining a healthy range of heart rate variability.

Understanding variability is critical in assessing fetal health during monitoring. The amplitude of variability reflects the autonomic regulation of the heart. Marked variability could indicate that the fetus is neurologically intact and responding well to the environment. It is monitored closely during labor and delivery to ensure the well-being of the fetus, and patterns of variability can provide insights into fetal distress or potential complications.