At 23 weeks pregnant, your uterus reaches roughly 23 centimeters from your pubic bone to the top of the uterus, a measurement known as fundal height. That puts it somewhere between your belly button and your breasts, about the size of a large grapefruit or papaya. It’s a dramatic change from its pre-pregnancy size, which is closer to a small lemon.
How Fundal Height Works
Starting around week 18 to 20, your provider begins measuring the distance from the top of your pubic bone to the top of your uterus with a flexible tape measure. This fundal height, measured in centimeters, roughly matches your week of pregnancy. At 23 weeks, a normal reading falls between about 21 and 25 centimeters. At 30 weeks, you’d expect roughly 30 centimeters, and so on.
This rule of thumb holds reliably from about week 20 through week 36. Before and after that window, the correlation is less predictable. The measurement is a quick screening tool, not a precise diagnostic. Being off by up to 2 centimeters in either direction is completely normal and not a reason for concern. Factors like your height, body composition, bladder fullness, and whether you’re carrying twins can all shift the number slightly.
What Happens If Your Measurement Is Off
If your fundal height is more than 2 centimeters above or below your gestational age, your provider will typically follow up with an ultrasound to check on things. A measurement that’s larger than expected could reflect extra amniotic fluid, a larger baby, or simply the way you carry. A smaller measurement might suggest slower fetal growth or lower fluid levels. In most cases, the ultrasound confirms everything is fine. The fundal height check is deliberately designed to cast a wide net so that the rare issue gets caught early.
Where Your Uterus Sits at 23 Weeks
By this point in the second trimester, your uterus has risen well out of your pelvis and sits noticeably above your belly button. It’s no longer tucked behind your pelvic bones where it spent the first trimester. You can often feel the top of it yourself by pressing gently on your abdomen a few centimeters above your navel.
This upward growth means your internal organs are starting to get squeezed. Your bladder takes the most direct pressure, which is why the frequent trips to the bathroom from early pregnancy tend to intensify rather than fade. Your intestines and stomach get pushed upward and slightly to the sides, which can trigger heartburn or indigestion even if you’ve never dealt with those before. The expanding uterus also puts tension on the round ligaments that anchor it to your pelvis, and that’s behind much of the hip and lower back soreness that shows up around this stage.
How Quickly the Uterus Grows From Here
At 23 weeks you’re near the end of the second trimester, and the uterus still has a lot of expanding to do. It will continue growing at roughly 1 centimeter per week through week 36. By the end of the third trimester, it reaches up near your rib cage, roughly 36 centimeters from the pubic bone, and holds around 5 liters of volume between the baby, the placenta, and amniotic fluid. That’s a nearly 500-fold increase from its pre-pregnancy volume of about 10 milliliters.
The growth rate isn’t perfectly linear. You may notice bigger jumps during weeks when the baby is going through a growth spurt, and your belly may seem to pop outward suddenly after weeks of gradual change. This is normal. What matters at each visit is that the fundal height is tracking reasonably close to your gestational age, not that it follows a perfectly smooth curve.
What 23 Weeks Feels Like Physically
The size of your uterus at this stage is large enough to be clearly visible but not yet large enough to significantly restrict your movement. Most people at 23 weeks describe feeling noticeably pregnant but still relatively comfortable compared to the third trimester. You can expect your center of gravity to start shifting forward, which may change the way you stand and walk without you fully realizing it.
Common physical effects tied directly to uterine size at this point include a need to urinate more often, occasional round ligament pain (sharp twinges on one or both sides of your lower belly when you move quickly), and mild shortness of breath as the uterus begins to crowd the space below your diaphragm. Sleeping on your back may start feeling uncomfortable because the weight of the uterus can press on a major blood vessel. Sleeping on your side, particularly the left side, takes that pressure off and tends to feel better.