A peanut ball is a peanut-shaped exercise ball placed between your legs during labor to open your pelvis and help your baby move down. It’s especially useful if you have an epidural and can’t easily change positions on your own. The ball works by separating and slightly elevating your legs, creating more room in the birth canal for your baby to descend and rotate into a good delivery position.
Choosing the Right Size
Peanut balls come in several sizes, and picking the right one matters. A ball that’s too large will push your legs uncomfortably far apart, while one that’s too small won’t open your pelvis enough to make a difference.
- 40 cm: Best if you’re 5’3″ or shorter, or have shorter legs.
- 50 cm: Fits most people between 5’3″ and 5’6″.
- 60 cm: Best for those taller than 5’6″.
- 70 cm: Used for sitting positions only, not placed between the legs.
Many hospitals stock peanut balls in their labor and delivery units, so ask your nurse what sizes are available. If you’re planning to bring your own, slightly underinflate it for comfort. A softer ball conforms better to your body and stays in place more easily.
The Side-Lying Position
This is the most common way to use a peanut ball and the go-to position if you have an epidural. Lie on one side and place the peanut ball between your legs so that your top leg rests over the middle of the ball. Your knee and lower leg should drape over the narrowed center, while the ball’s wider ends support your thigh and ankle. This gently separates your knees and opens the pelvic outlet.
You want your top hip to be noticeably higher than your bottom hip. If you feel like your legs are barely apart, the ball may be too small. Your bottom leg can stay relatively straight or bend slightly for stability. A pillow under your head and behind your back helps you stay comfortable and keeps you from rolling.
Switch sides roughly every 30 to 60 minutes. Alternating isn’t just about comfort. It changes the angle of pressure inside your pelvis, which encourages your baby to rotate and descend. Your nurse or birth partner can help you reposition the ball each time you turn.
The Semi-Sitting Position
Raise the head of the hospital bed to about a 45-degree angle so you’re reclined but not fully upright. Place the peanut ball between your bent knees with the ball’s length running vertically. Let your knees fall open around the wider ends. This position opens the top of your pelvis (the inlet), which is helpful earlier in labor when your baby is still high.
Semi-sitting also works well during the later pushing stage because it combines gravity with pelvic opening. You can grip the sides of the ball with your inner thighs to give yourself something to brace against during contractions.
The Tuck Position
The tuck is a variation of the side-lying position that creates even more pelvic space. Lie on your side and bring your top knee up toward your chest, then place the peanut ball under that bent leg so both your knee and shin rest on the ball. Your bottom leg stays extended or only slightly bent.
This asymmetric posture tilts your pelvis unevenly, which can be particularly helpful if your baby is facing your belly (occiput posterior, sometimes called “sunny-side up”). The uneven angle encourages the baby to rotate into a face-down position, which is easier to deliver. If your care team mentions that your baby is posterior, the tuck position on alternating sides is one of the first things worth trying.
The Semi-Sitting Lunge
This is another asymmetric option. While semi-reclined in bed, place the peanut ball to one side of your body and drape one leg over it, keeping the other leg bent with the foot flat on the bed. The result is a gentle lunge that opens one side of your pelvis more than the other. Like the tuck, this promotes rotation and can help a baby who seems “stuck” at a particular station.
Alternate the lunge side every 30 to 60 minutes, just as you would with the standard side-lying position.
When to Start Using It
You can begin using the peanut ball as soon as active labor is underway, during what’s called the first stage. The American College of Obstetricians and Gynecologists lists the peanut ball among supportive care measures that can assist labor progression. In clinical studies, the ball is typically introduced at the early active phase and repositioned every hour throughout labor.
During the first stage, the goal is to help your baby descend into the pelvis and rotate into a head-down, face-back position. The side-lying and tuck positions are most useful here. As you transition into the second stage (pushing), the semi-sitting position gives you the advantage of gravity while keeping your pelvis open. There’s no point at which you need to stop using the ball. Many people use it right up until delivery.
Why It Helps With an Epidural
Without an epidural, you can walk, squat, sway, and use a birth ball to keep your pelvis moving. An epidural limits or eliminates your ability to do any of that. The peanut ball solves this problem by passively holding your legs in positions that would otherwise require muscle control. It essentially mimics the pelvic opening you’d get from squatting or lunging, but while lying in bed.
This is why most of the research on peanut balls focuses on people with epidurals. In one evidence-based practice project at a university medical center, 81.6% of women who used the peanut ball during labor delivered vaginally. The ball’s effect on promoting spinal flexion also raises the angle between the uterus and spine, which helps move a posterior-facing baby into a better delivery position and can speed up labor.
Practical Tips for the Delivery Room
If your hospital provides peanut balls, you typically don’t need to request one in advance, but it doesn’t hurt to ask during your facility tour or when you call about your birth plan. If you’re bringing your own, pack it deflated with a hand pump. It takes only a minute or two to inflate.
Your birth partner plays a real role here. With an epidural, you’ll need someone to place the ball, adjust it when you shift, and help you turn to the other side on schedule. A good rhythm is to set a phone timer for 30 to 60 minutes as a reminder to switch. Your nurse will likely help with repositioning too, especially if continuous fetal monitoring is in place and the monitor belts need adjusting.
Comfort matters more than precision. If a position feels wrong or creates pressure in your hips or lower back, adjust the ball’s placement or try a different position. The ball should feel supportive, not strained. Placing a thin towel or pillowcase over the ball can keep it from sliding against hospital sheets.