Are Prolonged Decelerations Bad?

A sudden prolonged deceleration following rupture of membranes

with concomitant vaginal bleeding should prompt the physician to consider the possibility of a disrupted velamentous cord insertion (vasa previa), which can lead to rapid fetal exsanguination.

What does prolonged deceleration mean?

Prolonged deceleration. A decrease in FHR below the baseline of 15 bpm or more, lasting at least 2 minutes but <10 minutes from onset to return to baseline. A prolonged deceleration of 10 minutes or more is considered a change in baseline.

What causes prolonged decelerations in fetal heart rate?

They are caused by decreased blood flow to the placenta and can signify an impending fetal acidemia. Typically, late decelerations are shallow, with slow onset and gradual return to normal baseline. The usual cause of the late deceleration is uteroplacental insufficiency.