What the second trimester does to your posture and how to work with it
Nicola Tik
The second trimester brings a significant shift in how the body feels and moves. For many people it is also when the physical reality of pregnancy begins to affect everyday tasks in ways that were not noticeable before, including how comfortable it is to sit at a desk, stand for extended periods, or move through a normal working day. This article looks at what is happening in the body during this phase, how those changes affect posture and MSK comfort, and some practical ways to adapt so that daily life feels more manageable.
From around weeks thirteen to twenty-six, the body undergoes some of its most significant postural changes of the entire pregnancy. The growing bump shifts the body's centre of gravity forward, which places new and unfamiliar demands on the muscles of the lower back, hips, and pelvis. The lower back tends to increase its inward curve in response, a natural adaptation that can become a source of aching and stiffness when sustained over a long day of sitting or standing.
The hormone relaxin, which the body produces during pregnancy to allow the ligaments and connective tissues to soften and stretch in preparation for birth, also begins to have a more noticeable effect during this trimester. Joints that would normally be well supported by taut ligaments become a little more mobile and less stable. This is entirely normal, but it does mean the muscles surrounding those joints, particularly in the pelvis, hips, and lower back, have to work harder to compensate for reduced ligamentous support.
The ribcage also begins to widen during the second trimester to accommodate the growing uterus and support deeper breathing. For some people this produces a feeling of tightness or discomfort across the mid and upper back, particularly when sitting in a position that compresses the front of the body.
The forward shift in the centre of gravity and the increased curve in the lower back tend to produce a chain of postural adaptations that run upward through the spine. The upper back may round slightly in response, the shoulders can drift forward, and the neck adjusts to keep the head level, which places additional load on the muscles at the back of the neck and across the tops of the shoulders.
For desk workers this chain of adaptation is particularly relevant because sitting already encourages a similar pattern of postural change. Pregnancy in the second trimester can accelerate and intensify the neck, shoulder, and upper back tension that many desk workers experience regardless of pregnancy, while adding the lower back, hip, and pelvic discomfort that comes with the shift in centre of gravity.
The result for many people is a working day that feels increasingly effortful from a purely physical standpoint, with fatigue building more quickly than it did before and discomfort concentrating in the lower back, between the shoulder blades, and across the neck and shoulders.
The goal with desk setup during the second trimester is to reduce the sustained postural demand on the areas that are already under additional load, primarily the lower back, hips, and upper back.
Seat height is worth reviewing as the pregnancy progresses. A seat that allows the feet to rest flat on the floor, with the hips at roughly the same height as the knees or slightly higher, tends to reduce the compressive load on the lower back and pelvis. A footrest can be a useful addition if the chair height needed for the desk leaves the feet unsupported.
Lumbar support becomes increasingly important as the lower back curve increases. A small cushion or rolled towel placed in the curve of the lower back, or a chair with adjustable lumbar support, can help maintain a comfortable position without the lower back muscles having to work continuously to hold the spine upright.
Bringing the screen and keyboard closer reduces the need to reach forward, which can strain the lower back and shoulders. As the bump grows, the distance between the body and the desk changes, and it is worth regularly reassessing whether the setup still works rather than leaving it unchanged from before pregnancy.
Staying gently active through the day is one of the most consistently helpful things during the second trimester, both for MSK comfort and for general wellbeing. Prolonged sitting places sustained load on the lower back and pelvis, and the discomfort that builds through a long seated stretch tends to ease considerably with a short period of movement.
Standing up and moving briefly every forty-five minutes to an hour, even just to walk to another room and back, reduces the accumulation of lower back and pelvic tension through the day. Short walks during breaks, rather than remaining seated throughout, give the muscles and joints of the lower back and hips a chance to move through a fuller range and recover between periods of sitting.
Your VIDA pregnancy assessment can give you more tailored exercises and guidance based on your specific stage and how your body is feeling. It is worth completing if you have not already.
The second trimester is often described as the most physically comfortable of the three, and for many people it is. The nausea that can dominate the first trimester has often eased, and the significant heaviness and fatigue of the third trimester has not yet arrived. That said, the postural changes that begin in the second trimester continue to develop through the third, and the adjustments described here tend to become more rather than less relevant as the pregnancy progresses.
In the third trimester the bump is larger, the centre of gravity shifts further, and fatigue tends to increase. The same principles apply, with even more emphasis on regular movement breaks, lumbar support, and avoiding sustained positions that compress the front of the body or place prolonged load on the lower back and pelvis.
Some people experience discomfort around the front or sides of the pelvis, or into the hips and inner thighs, during the second trimester. This is related to the increased mobility of the pelvic joints under the influence of relaxin and the additional load the pelvis is managing. If this is familiar, it is worth being mindful of activities that involve standing on one leg, taking large steps, or moving the legs apart against resistance, as these can aggravate pelvic joint discomfort.
Keeping movements symmetrical where possible, sitting down to put on shoes or trousers, and avoiding carrying heavy loads on one side can all help manage pelvic discomfort during this phase. If pelvic girdle discomfort is significant or persistent, speaking to a physiotherapist who specialises in pregnancy is worth considering.