Prolonged decelerations last at least 2 minutes but not as long as 10 minutes.

If the deceleration lasts 10 minutes or more, it is considered a baseline change.

Causes can include maternal supine hypotension, epidural anesthesia, paracervical block, tetanic contractions, and umbilical cord prolapse.

Some of these are largely self-correcting, such as the deceleration following paracervical block, while others (maternal supine hypotension) respond to simple measures such as repositioning.

Other causes (such as umbilical cord prolapse) require prompt intervention to avoid or reduce the risk of fetal injury.