At 15 weeks pregnant, your uterus is roughly the size of a small melon or large grapefruit. It has filled your entire pelvis and is now starting to push upward into your abdomen. The top of the uterus, called the fundus, sits a few inches above your pubic bone at this point, roughly halfway between the pubic bone and your belly button.
Where Your Uterus Sits at 15 Weeks
Before pregnancy, the uterus is about the size of a small pear and tucked deep inside the pelvis. By 12 weeks, the top of the uterus rises to about the level of the pubic bone. At 15 weeks, it has climbed noticeably higher and is making the transition from a pelvic organ to an abdominal one. By 20 weeks, it will reach your belly button.
This means at 15 weeks you’re roughly at the midpoint between those two landmarks. If you press gently just above your pubic bone, you may be able to feel the firm, rounded top of the uterus for the first time. For some people, especially first-time pregnancies, it can still be tricky to locate from the outside.
How Big Is the Baby Inside
Your baby at 15 weeks measures about 4 inches long (crown to rump) and weighs around 2.5 ounces. That’s roughly the size of a pear you could hold in one hand. The baby is still small relative to the uterus itself, which also contains the placenta, amniotic fluid, and thickened uterine walls. All of that together accounts for why the uterus is significantly larger than the baby alone.
What the Growth Feels Like
This stage brings a shift in symptoms that directly reflects where the uterus now sits. Because it’s rising out of the pelvis, it puts less pressure on your bladder. Many people notice they don’t need to urinate as frequently as they did in the first trimester. That relief is temporary, though. As the uterus continues growing upward and then eventually drops lower again in late pregnancy, bladder pressure returns.
Constipation is common around this time. Pregnancy hormones relax the muscles of the bowel, slowing digestion. The expanding uterus also starts to crowd the intestines, which doesn’t help. You may also notice a stretching or pulling sensation low in your abdomen or along your sides as the round ligaments that support the uterus are being pulled taut by its increasing size. These quick, sharp twinges, often triggered by sudden movements, are one of the hallmarks of the second trimester.
Why Uterus Size Varies Between People
Not everyone’s uterus measures the same at 15 weeks, and that’s normal. Several factors influence how large your uterus feels and how much of a visible bump you have. If you’ve been pregnant before, your abdominal muscles have already stretched once, so the uterus tends to “show” earlier and can feel larger. The position of the uterus matters too. A uterus that tilts toward the front of the body creates a more obvious bump than one tilted toward the back.
Your body type, the amount of amniotic fluid, and the position of the placenta all play a role. Someone carrying an anterior placenta (attached to the front wall of the uterus) may feel a slightly fuller abdomen. None of these variations typically indicate a problem. Your provider will start measuring fundal height at prenatal visits, usually beginning around 20 weeks, to track growth over time.
What Changes in the Coming Weeks
Between 15 and 20 weeks, the uterus grows rapidly. It roughly doubles in volume during this stretch as the baby goes through a major growth spurt. By 20 weeks, the fundus reaches the belly button, and from that point forward, it climbs about one centimeter per week. At 15 weeks you’re in the early part of that acceleration, which is why many people start “popping” visibly right around now. Clothes that fit last week may suddenly feel snug across the lower belly, and maternity pants often become necessary somewhere between weeks 14 and 18.