The use of non-pharmacological comfort tools in labor has grown significantly, and the peanut ball has emerged as a popular specialized aid. This inflatable device is primarily utilized to promote progress during labor, particularly for women who are confined to bed. Its design and function explain why this simple tool is now a routine feature in many hospital delivery rooms.
Defining the Peanut Ball and Its Purpose
The peanut ball is an inflatable device distinguished by its oblong, hourglass shape, which tapers in the middle like a peanut shell. It is available in various diameters, such as 40 cm, 50 cm, and 60 cm, to accommodate different patient heights.
Its primary function is to provide stable support for the legs and hips of a woman who must remain in bed, such as those who have received an epidural or are experiencing fatigue. By supporting the legs, the peanut ball allows for dynamic changes in body positioning when mobility is limited. This support prevents the pelvis from collapsing inward, which can happen when lying flat without a prop.
The Biomechanics of Pelvic Opening
The effectiveness of the peanut ball is rooted in the biomechanics of the female pelvis during childbirth. The ball’s shape allows the hips and thighs to be placed in an asymmetrical position, which maximizes the dimensions of the pelvic pathways as the baby descends.
When positioned between the legs, the ball promotes hip abduction and external rotation, increasing the space within the pelvic inlet and midpelvis. In a side-lying position, elevating the upper leg creates an asymmetrical stretch that alters pelvic alignment. This change in geometry helps facilitate fetal descent and internal rotation needed for a vaginal birth. The ball mimics the beneficial pelvic opening achieved by squatting or kneeling while the woman is resting in bed.
Practical Application During Labor
The peanut ball is typically introduced during the active phase of labor, often after an epidural has been administered and the woman is confined to the bed. One of the most common applications involves the side-lying position, where the ball is placed between the knees or ankles, often with the top leg draped over the ball’s narrow center. This position is particularly helpful for opening the pelvic inlet when the baby is still high in the pelvis.
Another variation is the semi-reclining position, where the woman leans back and drapes one leg over the ball while the other leg remains to the side. For maximum effectiveness, the care team should ensure the ball size is appropriate for the woman’s height and the position being used. Changing positions frequently, such as every 30 to 60 minutes, is recommended to encourage continuous movement of the baby through the pelvis.
Documented Outcomes and Safety Considerations
Research suggests that using a peanut ball is a successful intervention for women laboring with an epidural, showing benefits for the duration of labor and the mode of delivery. A meta-analysis indicated that women who used the peanut ball experienced a shortened duration of the first stage of labor, often by around 53 minutes. Studies have also shown a lower risk ratio for cesarean section.
Safety requires proper sizing and attentive monitoring, as a ball that is too large can over-abduct the hips and cause discomfort or injury. The most common sizes used are 40 cm for women under 5’3″ and 50 cm for those 5’3″ to 5’6″. Although the peanut ball is non-invasive, trained staff must assist with positioning and monitoring to ensure maternal comfort and fetal well-being are maintained.