FHR Variable Decelerations — Recognition & Response

Variable decelerations are abrupt drops in fetal heart rate (FHR) caused by umbilical cord compression. "Abrupt" means onset to nadir in less than 30 seconds, distinguishing them from the gradual onset of late decelerations. They vary in shape, depth, duration, and timing relative to contractions — no two look alike, which is their defining visual feature. By definition, the drop is ≥15 bpm below baseline and lasts ≥15 seconds but less than 2 minutes. They are the most common deceleration pattern in labor, especially during active labor and second stage when cord compression from descent, oligohydramnios, or nuchal cord is likely. Isolated, brief variables with a quick return to baseline and preserved variability are generally benign. They become concerning when they are recurrent (occurring with ≥50% of contractions over 20 minutes), progressively deeper, slower to recover, or accompanied by loss of variability or absent accelerations — features sometimes called "atypical" variables. The initial nursing response is to reposition the client (side-lying, hands-and-knees) to relieve cord compression. If repositioning fails, discontinue oxytocin if infusing, increase IV fluids, and notify the provider. Amnioinfusion may be ordered to cushion the cord when oligohydramnios is contributing.