Why your upper back and ribs can feel uncomfortable during pregnancy
Nicola Tik
Upper back and rib discomfort is something many people notice from mid-pregnancy onwards, and it can range from a dull ache across the back to a sharper, more localised sensation under the ribs. Understanding what is driving it can help make sense of what your body is going through.
As your baby grows, your uterus expands upward into the abdominal cavity, gradually pushing the diaphragm, the dome-shaped muscle that sits at the base of your lungs and controls breathing, upward. This reduces the space available for the lungs to expand fully, which is why many people notice their breathing feels slightly shallower or more effortful from mid-pregnancy onwards.
To compensate, the ribcage itself widens and flares outward. This is a normal and necessary adaptation, but it places new demand on the muscles and joints of the upper back and the cartilage that connects the ribs to the breastbone. The result is that the upper back and rib area is managing a different kind of load than it is used to, and this can manifest as aching, tightness, or sensitivity around the ribs and into the mid and upper back.
The postural changes that develop across pregnancy, the forward shift in centre of gravity and the increasing curve in the lower back, have a knock-on effect higher up the spine. As the lower back arches more, the upper back often rounds forward in response, and the shoulders follow. This increased rounding through the thoracic spine, the section of the spine that runs through the mid and upper back, can compress the rib joints and contribute to the sense of tightness or aching that many people describe.
Breasts becoming heavier from early pregnancy also increases the load through the upper spine and can pull the shoulders forward further, adding to the tension across the upper back and between the shoulder blades.
In the earlier months, upper back and rib discomfort is often mild and comes and goes. From the second trimester onwards, as the uterus rises higher and the ribcage continues to widen, symptoms tend to become more consistent. By the third trimester, when the baby may be pressing directly against the ribs, localised rib discomfort is particularly common and can feel quite sharp with certain movements or positions.
It is also common for discomfort to shift depending on the baby's position, easing on some days and feeling more pronounced on others.
For most people, upper back and rib discomfort eases after birth once the uterus contracts and the ribcage gradually returns to its usual position. In the meantime, being aware of what tends to aggravate it and what helps is a useful starting point, which is what the next article covers.