The purpose of this study is to quantify the reliability of the gravity flow technique to accurately validate the position of the epidural needle tip when performing lumbar epidural analgesia in laboring women. This gravity flow technique was first described 26 years ago in 1991, and has been at NYU Langone for 15 years, since 2002. The technique has not been formally studied and this study is designed to enable assessment of the success rate of the gravity flow technique.