A peanut ball is a peanut-shaped inflatable ball used primarily during labor to open the pelvis and help the baby descend, especially when an epidural limits your ability to move freely. It can shorten labor, reduce the chance of a cesarean delivery, and help rotate a baby into a better position for birth. Peanut balls also have a second life in physical therapy, particularly for building core strength in children.
Why a Peanut Ball Works During Labor
The peanut shape fits between your legs in a way a round birth ball cannot, making it ideal for use while lying in bed. When positioned correctly, it widens the pelvic opening and encourages spinal flexion, which raises the angle between your uterus and spine. This gives the baby more room to rotate and move downward through the birth canal.
The clinical results are meaningful. In a study published in The Journal of Perinatal Education, women who used a peanut ball during labor had a cesarean rate of 10%, compared to 21% among women who did not use one. First-stage labor was about 29 minutes shorter, and the pushing stage (second stage) was 11 minutes shorter. The effect on cesarean rates held even after accounting for first-time mothers, who generally face longer labors: peanut ball users were less than half as likely to need a cesarean.
Choosing the Right Size
Peanut balls come in four standard sizes: 40 cm, 50 cm, 60 cm, and 70 cm. The right one depends on your height and leg length.
- 40 cm: Best for shorter legs or petite frames
- 50 cm: Fits most average-height people
- 60 cm: For taller individuals
- 70 cm: Designed for sitting on, not for placing between the legs
If the ball is too large, it will push your legs apart uncomfortably and strain your hips. Too small, and it won’t open the pelvis enough to be effective. When in doubt, a 50 cm ball works for the majority of people. Many hospitals stock them, but if you’re planning ahead, confirm with your birth facility or bring your own.
Side-Lying Position
This is the most common way to use a peanut ball during labor. Lie on your side and place the ball between your legs so your upper leg rests over the wider part of the ball. Your knee and lower leg should hook around the narrower center section, like you’re hugging the ball with your leg. This lifts the upper leg and opens the pelvis, creating more space for the baby to descend or rotate.
The side-lying position is especially useful when the baby is facing your belly (occiput posterior), a position that often causes back labor and slower progress. Alternating between your left and right sides encourages the baby to turn into a more favorable, face-down position. If one side feels significantly more comfortable than the other, that’s fine. Your comfort level is a reliable guide for placement.
Semi-Reclined Position
In this position, you sit partially reclined in the hospital bed (what clinicians call semi-Fowler’s position) with the peanut ball placed between your bent knees. This opens the pelvic outlet in a different way than side-lying, targeting the lower portion of the pelvis where the baby exits. It can be a good option when you need a break from lying on your side or when the baby has already descended and you’re closer to pushing.
How Often to Switch Positions
If you have an epidural, switching positions every 30 minutes is the standard recommendation. This prevents prolonged pressure on one side, keeps blood flow even, and gives the baby repeated opportunities to shift and rotate. Your nurse or midwife will typically help you reposition since epidural numbness makes it difficult to move on your own.
Start using the peanut ball once your epidural has taken full effect and you’re comfortable. There’s no need to wait for a specific stage of labor. The ball can stay in use through both early and active labor, right up until pushing begins.
Using a Peanut Ball Without an Epidural
While most of the research focuses on epidural users (because they’re the ones confined to bed), a peanut ball works for unmedicated labor too. You can use the same side-lying and semi-reclined positions during rest periods between contractions. Some people also sit upright straddling the ball, using the 70 cm size, to gently rock the hips and relieve pressure during contractions. The key difference is that without an epidural, you have full mobility, so the peanut ball becomes one tool among many rather than your primary way to stay active in bed.
Peanut Ball Exercises for Children
Outside of labor, peanut balls are a staple in pediatric physical therapy because their shape is more stable than a round exercise ball, making them safer and less intimidating for kids.
Straddle sitting is one of the simplest exercises. A child sits on the ball with legs on either side, and the slight instability challenges their core muscles and postural control without requiring any complicated movement. For upper body strength, prone walk-outs work well: the child lies stomach-down on the ball and walks their hands forward on the floor, building arm strength and core stability at the same time.
Modified sit-ups on the peanut ball target trunk stability. Adding a reaching motion, like touching a toy held to one side, engages the oblique muscles along the sides of the torso. For kids working on balance, leaning against the ball while standing and lifting one foot practices single-leg balance in a supported way, building hip and ankle strength before they’re ready for freestanding balance on one foot.
The peanut ball also serves a sensory role. For children who seek deep pressure or feel overwhelmed by sensory input, rolling the ball over their body provides proprioceptive input, the kind of firm, steady pressure that helps the nervous system calm down. This makes it useful not just for strength work but as a regulation tool during moments of stress or overstimulation.