You can start using an exercise ball at any point during pregnancy, but the benefits shift depending on the stage. In early pregnancy, it helps with posture and back comfort. In the third trimester and during labor, it becomes a more targeted tool for encouraging your baby into a good position and managing pain during contractions.
Early Pregnancy: Comfort and Core Support
There’s no reason to wait until late pregnancy to start sitting on an exercise ball. Many people begin using one in the first or second trimester simply as a replacement for a desk chair or couch seat. The unstable surface keeps your core muscles lightly engaged and encourages you to sit upright rather than slumping, which helps with the low back pain that often starts creeping in well before the third trimester.
At this stage, the ball is mostly a comfort tool. Tilting your hips back and forth or side to side while sitting on it keeps your hips and lower back mobile, which matters as your joints start loosening from hormonal changes. Even 15 to 20 minutes of sitting on the ball during the day can break up long stretches of sedentary time.
Third Trimester: Encouraging Baby’s Position
The exercise ball becomes especially useful from about 32 weeks onward, when your baby is getting into position for birth. Sitting on the ball with your knees lower than your hips tilts your pelvis forward, which gives your baby more room to settle head-down in the optimal position. Gentle circular hip movements and figure-eight motions while seated can encourage this further.
The key here is hip mobility. When you sit on a couch or soft chair, your pelvis tends to tuck under, which can make it harder for your baby to rotate into a favorable position. On the ball, your pelvis stays open and mobile. Many midwives recommend spending time on the ball daily in the final weeks of pregnancy for this reason.
During Labor
This is where the exercise ball has the strongest research support. A randomized controlled study found that women who used a birth ball during active labor experienced significantly shorter labor times, both during the dilation phase and during delivery itself. The study also found the ball significantly reduced labor pain and recommended it for all low-risk pregnancies because it helps with fetal descent and cervical dilation.
During contractions, sitting on the ball and gently bouncing or rocking your hips provides both pain relief and distraction. Leaning forward over the ball while kneeling is another popular position that takes pressure off your back and lets gravity help your baby move down. Many hospitals and birthing centers keep exercise balls on hand for exactly this purpose.
A peanut-shaped ball (narrower in the middle) is useful for a different set of positions. In the asymmetrical side-lying position, you lie on your side and drape your top leg over the peanut ball in a bent position. This opens your pelvis asymmetrically, which helps the baby navigate through during labor. This position works well even if you have an epidural and can’t sit upright.
Choosing the Right Size
The ball needs to be the right size for your height, or you won’t get the pelvic positioning that makes it useful. When you sit on it, your knees should be about 10 centimeters (4 inches) lower than your hips, creating a slight downward slope from hip to knee. The general sizing guide:
- Up to 5’8″ (1.73m): A 65cm ball works best.
- Taller than 5’8″: Go with a 75cm ball.
If you’re shorter than 5’4″, you can buy a 65cm ball and simply inflate it a bit less, to about 60cm, so your feet still reach the floor comfortably. Your feet should always be flat on the ground with your knees roughly hip-width apart. If you’re on your toes, the ball is too tall.
Staying Safe on the Ball
The biggest practical risk is losing your balance, especially in the third trimester when your center of gravity has shifted. Use the ball on a non-slip surface like carpet or a yoga mat, and keep it away from stairs or sharp furniture edges. The first few times you sit on it, have something sturdy nearby you can grab if you feel unsteady.
Look for a ball labeled “anti-burst,” which means it will deflate slowly rather than pop if punctured. Most quality exercise balls support well over 250 kilograms (550 pounds), so weight capacity is rarely a concern. Inflate it according to the manufacturer’s instructions and check it periodically for wear or soft spots. If the ball feels squishy or doesn’t hold its shape when you sit on it, it’s either under-inflated or needs replacing.
Simple Movements to Try
You don’t need a complicated routine. A few basic movements cover the main benefits:
- Hip circles: Sit on the ball and slowly rotate your hips in a circle, as if you’re stirring a pot. Switch directions every 10 rotations or so.
- Pelvic tilts: Rock your hips forward and backward while seated. This loosens the lower back and gently stretches the pelvic floor.
- Side-to-side rocking: Shift your weight from one hip to the other. This keeps your hip joints mobile and can ease sacroiliac pain.
- Gentle bouncing: Small, controlled bounces while seated. This is especially useful during early labor contractions.
- Kneeling lean: Kneel on the floor and drape your upper body over the ball. This takes pressure off your lower back and is a good resting position in late pregnancy or labor.
None of these movements should feel strained or painful. The ball is a low-intensity tool. If something feels off, shift to a different position or take a break. Most people find that even five to ten minutes of gentle movement on the ball provides noticeable relief from the hip and back tension that builds throughout the day.