Ambulation During Neuraxial Analgesia in Obese Patients: A Pilot Study
Authors: Suresh Sunitha , Seiler Arran , Arnolds David , Gonzalez Maritza , Cole Nadia , Silver Richard , Scavone Barbara , Dude Annie 
Published: July 2024

Objective: Obese patients are known to have prolonged labors and an increased risk of cesarean delivery in comparison to their normal weight counterparts. Movement has previously been shown to have beneficial effects on the labor process; however, neuraxial analgesia is often recommended in obese women and in common practice limits mobility. The benefits of continuing to ambulate during neuraxial analgesia are not known. As prior studies have postulated a soft tissue dystocia as a potential etiology for prolonged labor among obese patients, ambulation and encouraged movement throughout the labor process may be of particular benefit for these patients. The purpose of this study was to evaluate the feasibility of ambulation with neuraxial analgesia in nulliparous obese patients admitted for labor.

Study Design: This is a pilot study conducted at a single tertiary care center. Patients with a BMI of >=35 were approached if they were nulliparous, term, and planned vaginal trial of labor. Patients were excluded if there were contraindications to ambulation, including magnesium administration. Participants were identified at >=34 weeks estimated gestational age through clinic templates and induction of labor schedules, and were approached either in person or with a standard phone consent. Combined spinal-epidural analgesia was initiated per our institution’s policy, with the exception that during the latter portion of the study the test dose was eliminated in order to decrease the immediate motor block from this dose. Following epidural catheter placement, serial blood pressure measurements and motor assessments were completed to ensure safety including a straight leg test and a step stool test. Patients who passed these assessments were enrolled in the trial. Patients were encouraged to ambulate for 20 minutes of every hour while maintained on fetal and uterine telemetry. Ambulation was discouraged after complete dilation. Demographics and delivery outcomes were collected.

Results: 105 patients were identified for consent for the trial, of whom 20 were ineligible for the study, 20 were not approached, and 40 declined study participation, leaving 25 patients who were consented. Of those 25, 14 completed the study. Reasons for not completing the study included ineligible by motor assessment, BMI less than 35 at time of delivery admission, preterm delivery, withdrawal, complete dilation at time of epidural without time to ambulate, magnesium administration during labor. A total of 14 participants were enrolled in the pilot trial, of which 11 were able to ambulate. The average BMI of participants was 43 kg/m2. Patients received epidural analgesia at a median cervical dilation of 4 cm and the average time from initiation of epidural analgesia to delivery was 15.4 hours. 65% of patients enrolled had a cesarean delivery. Of the 5 patients with a vaginal delivery, there was 1 shoulder dystocia. The median time spent ambulating was 58.5 minutes, with a range of 20-230 minutes. No patients fell during the trial. While one patient developed a spinal headache, it was not thought to be related to ambulation.

Conclusions: A pilot trial of ambulation during neuraxial analgesia demonstrated no safety concerns among an obese nulliparous population. This pilot study was underpowered and is not designed to determine if there is an effect of ambulation with neuraxial analgesia on mode of delivery. Strengths of this study were interdisciplinary collaboration and biologic plausibility of decreased cesarean delivery through ambulation. Limitations included a low enrollment rate and the COVID pandemic, which halted the study as well as limited patients from being able to ambulate in the hallways. A larger study is needed to assess the efficacy of this intervention.