What FHR feature indicates normal fetal acid-base status?

The presence of moderate variability and fetal heart rate (FHR) accelerations indicates a normal fetal acid-base status. Moderate variability refers to fluctuations in the fetal heart rate that are within the range of 6 to 25 beats per minute, demonstrating a healthy response from the fetal autonomic nervous system. This kind of variability signals that the fetus is well-oxygenated and has a functioning central nervous system.

FHR accelerations, which are temporary increases in the heart rate that occur in conjunction with fetal movements, further reflect a reactive and well-oxygenated fetal state. When these two features—moderate variability and accelerations—are observed together, they strongly suggest that the fetus is not experiencing any significant distress or compromise in its acid-base status.

In contrast, the other features mentioned—such as late decelerations, a high baseline heart rate, and absence of variability—are typically associated with fetal distress or compromised oxygen status. Late decelerations often indicate uteroplacental insufficiency, while an elevated baseline heart rate might be a signal of fetal hypoxia. Therefore, identifying moderate variability and accelerations is essential for assessing a normal fetal condition.