Do Peanut Shaped Birthing Balls Reduce the Length of Labor in Patients With Epidural Analgesia?
Phase: NA
Conditions: Labor
Sponsor: Wake Forest University Health Sciences

 
 
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Title: Do Peanut-Shaped Birthing Balls Reduce the Length of Labor in 
Patients with Epidural Analgesia?  
 
Primary Investigator: Robert D’Angelo, MD  
 
Background:  
In the United States approximately 2/3 of laboring women receive epidural or combined 
spinal-epidural (CSE) analgesia.1 A 1998 meta-analysis found that although epidural 
analgesia increases the length of labor by 56 min, it does not increase the incidence of 
cesarean delivery or forceps delivery for dystocia.2 Additionally, maternal satisfaction is 
significantly increased in patients with epidural analgesia. For a number of reasons 
unrelated to epidural analgesia, the incidence of cesarean delivery has increased during the 
past 20 years, and in 2013, 32.7% of women in the United States had a cesarean delivery.3 
Because more than 90% of women that have a cesarean delivery have a repeat cesarean for 
subsequent deliveries and cesarean delivery is associated with more serious complications 
than vaginal delivery, there are national initiatives to reduce cesarean delivery rates.4  
In a recently published study conducted by nurses and doulas in an Arizona hospital, the use 
of peanut-shaped birthing balls5 (see Appendix, figure 1) in patients with epidural labor 
analgesia significantly reduced the length of labor and the incidence of cesarean delivery.6 
Following epidural insertion and informed consent, patients were randomized to labor using 
a peanut ball or labor without using a peanut ball until complete cervical dilatation. The 
length of labor was reduced by 113 min (Stage 1 labor by 90min and Stage 2 labor by 23min) 
and the incidence of cesarean delivery was reduced by 57% (from 23.7 to 10.3%). No patient 
in either group experience complications. It is theorized that the birthing balls enhance 
labor by increasing the pelvic diameter, thus allowing for more rapid descent of the fetal 
head.  
These results are incredibly significant for a single simple intervention and, if replicated, 
may have large scale public health implications. The purpose of the current study is to 
determine if a low-cost, safe, and easy to use physical prop actually improves labor 
outcomes. Thus, the hypothesis of this randomized prospective study is that use of peanut-
shaped birthing balls following epidural administration will significantly reduce the length of 
labor and the incidence of operative delivery.  
 
Method: After informed consent, up to 240 nulliparous parturients planning to request 
epidural analgesia for their labor pain will be enrolled in the study. Following CSE analgesia 
(patients will be standardized to the CSE technique because it has been suggested that CSE 
analgesia speeds the rate of cervical dilatation when compared to epidural analgesia7), 
patients will be randomized to either have a 45cm peanut-shaped birthing ball placed 
between the knees for the duration of stage 1 labor (until complete cervical dilation) or to 
labor as is customary without an object placed between the knees. To determine the impact 
of the birthing balls on the labor curve, patients will have a cervical exam within 15min of 
epidural placement and every four hours (or when clinically indicated) until complete 
cervical dilation. In addition, all patients will have a Bishop’s score (used to assess the odds 
of successful vaginal birth) estimated by the obstetric team.8 Patients will  be positioned 

 
 
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during labor in the lateral or semi-Fowler positions (see Appendix, figure 2) and asked to 
turn sides every hour. The length of labor from epidural insertion to delivery (the primary 
outcome) and the mode of delivery (secondary outcome) as well as usual variables such as 
the frequency and incidence of needing epidural top-ups, pain intensity, vital signs, fetal 
heart rate tracing, and patient satisfaction will be obtained throughout the course of labor 
and delivery. Following delivery, neonatal weight and Apgar scores will be recorded and all 
patients will be evaluated the day after delivery for satisfaction and any complications such 
as back or hip discomfort. Exclusion criteria: age<18, non-English speaking, multiparous 
women, patients with preeclampsia with documented abnormal liver enzyme function 
changes, contraindications to receiving neuraxial analgesia or any drugs used in this study.  
 
Statistics and Analysis:  
The primary outcome is the length of labor from epidural catheter insertion until delivery. 
Secondary outcomes include mode of delivery, maternal satisfaction and post-delivery 
complications. A power analysis was determined using historical data from epidural 
analgesia studies at FMC, recent FMC length of labor statistics, and estimations on length of 
labor reductions from the Banner Health report. To detect a 13% change in length of labor 
between groups with an estimated standard deviation of 46% from average length of labor 
(historical FMC mean =/- SD from epidural insertion to delivery is 325+/-150min), a 
minimum sample size of 101 per group is needed to provide a power of 0.8 and alpha of 
0.05. We will enroll up to a total of 240 subjects (120 per group for 2 groups) in anticipation 
of potential exclusions. The study will conclude when 202 evaluable patients have 
completed the study.  
 
Implications:  
If peanut-shaped birthing balls improve labor outcomes without complications, practice 
protocols will be revised to include the routine use of them during labor in the Women’s 
Center and possibly throughout all Novant birthing facilities. Further, publication of the 
results from this study will potentially affect public health policies.  
 
Risks:  
Epidural and CSE analgesia are commonly used (85%) in laboring patients at FMC 
(approximately 50-50 ratio). All of the usual risks for CSE labor analgesia apply including: 
inadequate anesthesia/analgesia, post dural puncture headache, backache, pruritus, 
nausea/vomiting, hypotension, as well as other very rare risks of respiratory depression, 
nerve injury, hematoma, infection and seizures. Although the Banner Health reports 
suggests that no patient experienced complications, we theorize that there is a small risk 
that use of the peanut-shaped birthing balls may increase the incidence of hip, pelvis or 
back discomfort following delivery. Patients will receive informed consent and will be 
treated as usual for any complications throughout labor and following delivery. All patients 
will be administered routine CSE medications throughout labor.  
 
Benefits:  
The results of this study may provide us a better understanding of the role of pelvic 
widening on labor outcomes.   
 

 
 
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Human Subjects Protection:  
Written informed consent will be obtained from each subject. Study team members or the 
research nurse will obtain informed consent from patients in labor and delivery suite after 
determining their fulfillment for eligibility criteria in participation. The study and informed 
consent will be reviewed with the patients while they are in the labor and delivery suite. 
Once signed, a copy of the informed consent form will be placed in the patient’s medical 
record and a copy will be given to the patient for their records.  
Confidentiality will be protected by collecting only information needed to assess study 
outcomes, minimizing to the fullest extent possible the collection of any information that 
could directly identify subjects, and maintaining all study information in a secure manner. 
The master study enrollment log containing the names, group allocation, and date of study 
will be kept secure in the department of OB Anesthesia, with access limited to designated 
study personnel. Following data collection subject identifying information will be destroyed 
at the earliest opportunity, consistent with data validation and study design, producing an 
anonymous analytical data set. Data access will be limited to study staff. Data and records 
will be kept locked and secured, with any computer data password protected. No reference 
to any identifiable individual participant will appear in reports, presentations, or 
publications that may arise from the study.  
 
Data and Safety Monitoring:  
The principal investigator will be responsible for the overall monitoring of the data and 
safety of study participants. The principal investigator will be assisted by other members of 
the study staff. A data safety monitoring committee made up of 1 obstetrician and 1 
obstetric anesthesiologist will be utilized and un-blinded to group allocation. They will 
review the interim results including review of vital signs, analgesic effects and the 
occurrence of any adverse events/side effects.  
 
Reporting of Unanticipated Problems or Serious Adverse Events:  
Any unanticipated problems, serious and unexpected adverse events protocol changes will 
be promptly reported by the principal investigator or designated member of the research 
team to the Institutional Review Board (IRB).  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
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References:  
1. Bucklin BA, et al. Obstetric anesthesia workforce survey: twenty-year update. 
Anesthesiology 2005; 103: 645-53.  
2. Halpern SH, et al. Effects of epidural vs. parenteral opioid analgesia on the progress of 
labor: a meta-analysis. JAMA 1998; 280: 2105-10.  
3. Martin JA, et al. Births: Final Report 2013. National Vital Statistics Report, 2015; Vol 64: 
Number 1. Also accessed at: http://www.cdc.gov/nchs/fastats/delivery.htm.  
4. Safe prevention of the primary cesarean delivery. Obstetric Care Consensus No 1. 
American College of Obstetricians and Gynecologists. Obstet Gynecol 2014: 123: 693-711.  
5. Isokinetics, Inc. www.isokineticsinc.com.  
6. Tussey CM, et al. Reducing length of labor and cesarean surgery rate using a peanut ball 
for women laboring with an epidural. Jr Perinatal Education 2015, 24: 16-24.  
7. Tsen LC, et al. Is combined spinal-epidural analgesia associated with more rapid cervical 
dilation in nulliparous patients when compared with conventional epidural analgesia? 
Anesthesiology 1999; 91: 920-5.  
8. Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol 1964; 24: 266-8.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
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Appendix:  
Figure 1. Peanut-shaped birthing ball.  
 
 
Figure 2. Lateral and Semi-Fowler Positioning During Labor.