Why Can't I Take a Deep Breath in My Third Trimester? How Ribcage Mobility Helps
Updated: Oct 8
Breathing feels harder in the third trimester because your growing uterus pushes your diaphragm up about 4 cm (1.5 inches). Your lower ribs are meant to widen to make room. When the rib joints along your mid-back are stiff, they can't widen fully, and breathing stays shallow. Gentle pregnancy chiropractic care can help restore that rib movement.
If you can’t take a deep breath in your third trimester, and everyone keeps telling you to "just take a deep breath and relax," you aren't doing anything wrong. Your belly is growing, your sleep is broken up, and your ribs may feel tight all day. Shallow breathing in late pregnancy is exhausting, and it's often more fixable than people think.
Why is it hard to take a deep breath in the third trimester?
Feeling short of breath in the third trimester is common and usually normal. Two things are happening at once.
Your diaphragm gets pushed up. As your uterus grows, it raises the resting position of your diaphragm by about 4 cm, so there's less room for your lungs to fill downward.
Your body breathes more. Pregnancy hormones, mainly progesterone, increase how much air you move each minute. Many women feel breathless even when they're resting.
Your ribcage is built to make up for this. During pregnancy, the lower ribcage grows about 5 to 7 cm (2 to 3 inches) around, and the angle where your lower ribs meet widens from roughly 68 degrees to 103 degrees. When your ribs can widen freely, your lungs keep almost all their capacity.
[Image suggestion, placed here. Alt text: Illustration of the lower ribcage widening during pregnancy as the diaphragm moves upward.]
How do your ribs and mid-back affect breathing during pregnancy?
Your ribs can only widen if the small joints where they attach to your mid-back (the thoracic spine) move well. Each rib hinges on the spine. When those joints get stiff from postural strain, the lower ribs can't flare out fully.
Pregnancy adds a lot of postural strain: a forward-shifting center of gravity, desk work, carrying a toddler, and sleeping on one side for weeks. When rib movement is blocked, your diaphragm can't expand sideways and toward your back. Your body makes up for it by breathing into the upper chest and shoulders.
Signs your shallow breathing may be rib-related:
A tight band feeling around your lower ribs
Breaths that stay in your upper chest or lift your shoulders
Stiffness or aching between your shoulder blades
Rib pain on one side, often under the breast, that's worse when sitting
Breathing that feels easier after a side stretch or a change of position
These signs point toward a mechanical cause, but they don't rule out a medical one. See the safety section below.
Why does shallow breathing make it harder to relax?
Slow, deep breaths with a long exhale help your nervous system shift into rest mode. Fast, shallow chest breathing goes along with the stress response. When stiff ribs keep you in chest breathing, the slow belly breath that helps you wind down is harder to reach.
That's why many moms notice it most at night. Lying down raises the uterus against the diaphragm even more, right when you're trying to settle into sleep. Restoring rib movement gives your breath, and your nervous system, more room to slow down. You can read more about how a mom's nervous system and her baby's are connected.
How does gentle pregnancy chiropractic help ribcage mobility?
Pregnancy chiropractic care for breathing focuses on getting the rib joints and mid-back moving again, using gentle contacts instead of force. At Bright Start Chiropractic, Dr. Michael checks how each section of your mid-back and ribcage moves, finds the joints that are restricted, and uses precise, low-force contacts to release them. [NEEDS: how you position pregnant patients, such as a pregnancy pillow, side-lying, or a table with a belly cutout.]
You can learn more about what a visit includes on our pregnancy chiropractic care page.
A 34-week patient's story:
Situation: A mom came into our West LA office at 34 weeks. She was exhausted because she couldn't catch a full breath, especially when trying to wind down at night.
What we found: Her lower mid-back and rib joints were clearly restricted.
What we did: No force and no aggressive manipulation. We used gentle, precise contacts to release the tightness in her rib joints.
Result: By the end of the visit she took her first full, deep belly breath in weeks, and her whole body visibly relaxed.
When should you call your OB or midwife about shortness of breath?
Most breathlessness in late pregnancy is normal, but some signs need medical care right away. Chiropractic care doesn't replace your OB or midwife. If you notice anything in the right column, call your provider, or call 911 if it's severe.
Usually normal in late pregnancy | Call your OB or midwife right away |
Breathlessness that built up gradually over weeks | Sudden or severe shortness of breath |
Worse on stairs or lying flat, better with rest or a new position | Chest pain, especially when you breathe in |
No other new symptoms | Coughing up blood |
Easier when sitting tall | A racing or pounding heartbeat |
Pain, swelling, or redness in one leg | |
Severe headache, vision changes, or sudden swelling in your face or hands | |
Blue or gray lips or fingertips, or fainting |
Frequently asked questions
Is it normal to feel short of breath in the third trimester?
Yes. Most pregnant women feel some breathlessness by the third trimester. The growing uterus pushes the diaphragm up about 4 cm, and pregnancy hormones raise your drive to breathe. Gradual breathlessness that eases with rest or a change of position is usually normal. Sudden or severe shortness of breath, chest pain, or a racing heartbeat needs a call to your OB or midwife right away.
Is chiropractic care safe in the third trimester?
For most low-risk pregnancies, chiropractic care adapted for pregnancy is considered safe. pregnancy adjustments use gentle, low-force techniques and positioning that keeps pressure off the belly. If you have a high-risk pregnancy, bleeding, placenta concerns, or preeclampsia, check with your OB or midwife before starting care. A pregnancy chiropractor should ask about your pregnancy history at the first visit.
Can rib pain during pregnancy make it harder to breathe?
Yes, it can. During pregnancy the lower ribs widen to make room for your lungs as the diaphragm moves up. When the small joints where the ribs meet the mid-back are stiff or sore, the ribs may not widen fully, and breathing shifts into the upper chest. Rib pain that comes with sudden breathlessness or chest pain should be checked by your medical provider first.
What position helps you breathe better in late pregnancy?
Sitting tall or standing gives your diaphragm the most room. Slumping in a soft couch compresses the lower ribs. At night, side-lying with a pillow under your belly and another behind your back usually feels easier than lying flat. Some women breathe more easily with their upper body propped on pillows. Raising your arms overhead for a few slow breaths can also open the lower ribs.
Does shortness of breath go away after giving birth?
For most women it improves quickly after delivery, because the uterus no longer pushes up on the diaphragm. The ribcage changes take longer. Research on pregnancy physiology shows the chest wall takes several months to return to its pre-pregnancy shape, and the lower rib angle often stays slightly wider. Ongoing rib or mid-back tightness after birth is worth having assessed.
If rib tightness or shallow breathing is making your third trimester harder, gentle care can help you breathe more fully before birth. Our West LA office sees moms through every stage of pregnancy, and through postpartum care after the baby arrives.
Book your pregnancy visit or call or text (424) 259-1432.
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