Ultrasound-Guided Landmark and Epidural Site Pain

participants who received US examination prior to epidural placement. The purpose of this group is to determine if US derived landmarks reduce pressure sensitivity.

participants who received US examination process but with the monitor turned off. The purpose of this group is to determine if the standard of care epidural placement technique will increase pressure sensitivity at the insertion site. The purpose of this group will also be to reduce the placebo effect from the US exam and to maintain blinding of the patient to their group status (US epidural or US sham epidural).

Spontaneous vaginal delivery without an Epidural The purpose of the control group is to serve as a baseline (or a measure of normal). The control participant's measurement will be compared to those that did receive treatments (either epidural alone or ultrasound and epidural). This information will tell the investigator how many women have back pain after spontaneous vaginal delivery. Participant must meet the inclusion requirements and not meet any of the exclusion requirements