At 10 weeks pregnant, your uterus is roughly the size of a large orange, measuring about 7 to 8 centimeters (around 3 inches) across. That’s roughly double its non-pregnant size, which is closer to a small pear or lemon. Despite this growth, your uterus is still tucked deep within your pelvis at this stage, which is why you likely won’t have a visible bump yet.
How the Uterus Changes by Week 10
Before pregnancy, the uterus is about 7 centimeters long and 5 centimeters wide, weighing around 70 grams. By week 10, it has expanded enough to accommodate a fetus with a crown-to-rump length of about 36 millimeters (roughly 1.4 inches) along with the amniotic fluid and placenta surrounding it. The walls of the uterus are thickening and its blood supply is increasing dramatically to support the pregnancy.
At this point, the top of the uterus (called the fundus) still sits below your pubic bone. This is why your healthcare provider won’t measure your belly with a tape measure yet. That external measurement, known as fundal height, doesn’t start until around 20 weeks, when the uterus has grown tall enough to rise above the pubic bone and be felt through the abdomen.
Why You Might Not Look Pregnant Yet
Because the uterus is still entirely within the pelvis at 10 weeks, most people don’t have an obvious baby bump. Any bloating or fullness you notice is more likely from hormonal changes slowing your digestion than from the uterus itself pushing outward. Some people, especially those who have been pregnant before, may notice their lower abdomen feels firmer or slightly rounder, but this varies widely from person to person.
If you’re carrying twins, the uterus may be slightly larger at this stage, though ultrasound studies show that individual fetuses in twin pregnancies measure nearly the same as singletons at 10 weeks, with crown-rump lengths within a millimeter of each other. The difference in uterine size with multiples becomes much more noticeable later in pregnancy.
What That Growth Feels Like
Even though the uterus is still small, you may already feel its expansion. Common sensations include a feeling of fullness or pressure low in the pelvis, mild cramping, or occasional sharp twinges on one or both sides of your lower abdomen. Those sharper pains are often caused by the round ligaments, two cord-like structures that anchor the uterus to the groin area. As the uterus grows, these ligaments stretch and widen, which can cause aching, cramping, or a sudden pulling sensation, especially when you change positions quickly.
Round ligament pain is most common during the second trimester, but it can start earlier. The discomfort is typically brief, lasting a few seconds to a minute, and tends to happen with sudden movements like standing up, rolling over in bed, or coughing. It’s a normal part of the uterus making room, not a sign that something is wrong.
How Uterine Size Is Checked at 10 Weeks
Since the uterus can’t be measured externally this early, your provider relies on ultrasound to assess how things are progressing. A 10-week ultrasound, often done transvaginally for the clearest image, measures the fetus from head to rump (crown-rump length) and checks for a heartbeat. This measurement is one of the most accurate ways to confirm your due date, because fetal size at this stage is remarkably consistent across pregnancies.
Your provider may also do a bimanual exam, placing one hand on your lower abdomen and two fingers inside the vagina to feel the size and shape of the uterus directly. At 10 weeks, the uterus should feel soft and slightly enlarged compared to its pre-pregnancy state. This quick physical check helps confirm that growth is on track between ultrasound appointments.
Uterine Growth Over the Coming Weeks
The growth from here is rapid. By 12 weeks, the uterus rises above the pelvic brim and can start to be felt through the abdomen. By 16 weeks, it sits roughly halfway between your pubic bone and your navel. At 20 weeks, the fundus reaches your belly button, and from that point through about 36 weeks, the distance in centimeters from pubic bone to fundus roughly matches the number of weeks pregnant you are.
By the end of pregnancy, the uterus will have expanded from that original pear size to hold a full-term baby, a placenta, and roughly a liter of amniotic fluid, stretching to about 500 times its original capacity. At 10 weeks, you’re still very early in that process, but the groundwork for all of that expansion is already well underway.