The aim of this study is to address the problem of epidural failure. The investigators theorize epidural failure can be due to inappropriate catheter movement and this may be related to the length of which the epidural catheter is inserted. The investigators will use electrical stimulation to determine if the catheter moved in the sacral direction with insertion.

The research participants will be pregnant women in Labor and Delivery ward of Stanford University hospital who request an epidural for labor analgesia.

In this study the patients will receive an epidural catheter in the same way as standard of care. The catheter will be inserted to 20cm and then electrically stimulated to document where it is placed by looking at the muscles effected. The catheter is then pulled back in 5cm increments and stimulated until the standard distance is achieved. For example, if loss of resistance happened at 5cm, the catheter would be inserted to 20cm, stimulated, pulled back to 15cm and stimulated, and finally to 10cm and stimulated.

Electrical stimulation of epidural catheters for confirmation of placement is a published and accepted technique. In this study, the investigators will perform electrical stimulation at incremental points during catheter pull back with documentation of where stimulation was seen.

Inclusion Criteria:

• Pregnant female requesting epidural for labor analgesia.
• Must meet standard inclusion criteria for safe epidural placement.
• Platelet count over 70,000, INR under 1.3.

Exclusion Criteria:

• Unable to safely place epidural catheter due to commonly accepted patient factors.