What condition could cause fetal bradycardia if the FHR baseline is 100/min for 15 min?

Fetal bradycardia, defined as a heart rate below 110 beats per minute for an extended period, can be influenced by several maternal conditions. When considering the cause of fetal bradycardia, maternal hypoglycemia is particularly relevant. In cases of hypoglycemia, the fetus can experience decreased oxygen and nutrient supply, leading to a compensatory decrease in fetal heart rate. This condition can induce metabolic stress on the fetal health, resulting in a slower heart rate as the body attempts to conserve energy.

Maternal hypertension tends to lead to decreased perfusion and can ultimately cause fetal distress, but it is more commonly associated with fetal tachycardia rather than bradycardia. Placental abruption can lead to fetal distress, yet it often presents with variable decelerations rather than a sustained bradycardia. Maternal fever can affect fetal heart rate patterns as well, typically presenting more as tachycardia due to increased metabolic demand and fetal distress.

Thus, maternal hypoglycemia stands out as a direct cause of fetal bradycardia due to its effects on metabolism and oxygenation for the fetus, resulting in a baseline heart rate of 100 beats per minute lasting for a significant period.