Before pregnancy, your uterus sits deep in your pelvis, just above and behind your bladder. It’s roughly the size of a small pear. Over the next 40 weeks, it grows dramatically and migrates upward through your abdomen, reaching nearly to your ribcage before dropping slightly in the final weeks. Here’s exactly where it sits at each stage.
Pre-Pregnancy and Early Weeks
In its normal resting position, the uterus is tucked entirely within the pelvic cavity. The cervix, its lower end, protrudes into the vagina. Most people never feel the uterus at this stage because it’s shielded behind the pubic bone. At around 5 weeks of pregnancy, it still feels about the same size as a small, unripe pear. By 6 weeks it’s comparable to a juice orange, and by 8 weeks it has grown to the size of a large navel orange.
During these early weeks, the uterus stays within the pelvis. You won’t see any visible bump yet, though you might notice bloating, increased urination (the growing uterus presses directly on the bladder), or a feeling of fullness low in the abdomen.
Rising Out of the Pelvis: Weeks 12 to 20
Around week 12, the uterus reaches the size of a grapefruit and completely fills the pelvic cavity. This is a turning point: it begins rising above the pubic bone and into the abdominal space. The top of the uterus, called the fundus, can now be felt just above the point where the pubic bones meet. For many people, this is when a visible bump first appears.
From there, the fundus climbs steadily. By 20 weeks, it reaches your belly button. This halfway mark is a convenient reference point that healthcare providers use during prenatal visits. If you place your hand flat at your navel at 20 weeks, you’re touching approximately where the top of your uterus sits.
The Centimeter-Per-Week Rule
Starting around week 20, your provider will likely measure something called fundal height: the distance in centimeters from your pubic bone to the top of the uterus. Between weeks 20 and 36, this number roughly matches your week of pregnancy, give or take 2 to 3 centimeters. So at 28 weeks, the fundus is typically about 28 centimeters above the pubic bone. At 32 weeks, roughly 32 centimeters.
A measurement that falls significantly outside that range can signal that the baby is larger or smaller than expected, that amniotic fluid levels are unusual, or that the baby is in an atypical position. It’s a simple screening tool, not a diagnosis, but it’s one reason your provider runs a tape measure over your belly at each visit.
Peak Height: Weeks 36 to 38
The uterus reaches its highest point around 36 weeks, when the fundus sits near the bottom of the ribcage, close to the base of the breastbone. At this stage it can press up against the diaphragm, which shifts upward by about 5 centimeters. That’s why deep breaths feel harder to take in late pregnancy. The upward pressure also compresses the stomach, contributing to heartburn and the feeling of being full after eating very little.
In the last two to four weeks before delivery, many babies (especially in first pregnancies) drop lower into the pelvis in a process often called “lightening.” When this happens, the fundus descends slightly, and breathing often becomes noticeably easier. The trade-off is renewed pressure on the bladder, which means more frequent trips to the bathroom.
What Happens to Your Other Organs
Your abdomen doesn’t have empty space waiting to be filled. Before pregnancy, most of it is occupied by the small and large intestines, with no real boundary separating the pelvic area from the abdominal cavity. As the uterus expands, it pushes these organs aside and upward. The intestines get crowded toward the back and sides of the abdomen, which is one reason constipation becomes more common. The stomach gets compressed and tilted, making it easier for acid to escape upward. Combined with hormonal changes that relax the valve between the stomach and esophagus, this compression is a major driver of heartburn during pregnancy.
The bladder, sitting directly in front of the uterus, takes pressure from the very beginning. In the first trimester, the growing uterus presses on it from above. In the third trimester, the baby’s head settles into the pelvis and compresses it again from a different angle. The middle trimester, when the uterus has risen above the pelvis but the baby hasn’t yet dropped, is often the stretch when bladder pressure eases up the most.
If You Have a Tilted Uterus
About 20 to 30 percent of people have a retroverted (tilted backward) uterus. In most cases, the uterus naturally shifts forward into an anteverted position by 12 to 14 weeks as it grows large enough to rise out of the pelvis. After that, it follows the same upward path as any other pregnancy.
In rare cases, a retroverted uterus doesn’t make that shift. It can become trapped in the pelvis, a condition called uterine incarceration. This prevents the uterus from expanding freely and can cause pain, difficulty urinating, and health risks for both parent and baby. If you know you have a tilted uterus and experience unusual pelvic pressure or urinary symptoms in the late first trimester, it’s worth bringing up at your next appointment.
After Delivery: The Return Trip
Once the placenta is delivered, the uterus immediately begins shrinking back to its pre-pregnancy size, a process called involution. About 12 hours after birth, the fundus can still be felt at roughly 1 centimeter above the belly button. From there it descends about 1 centimeter per day. By day 14, it has dropped back into the pelvic cavity and can no longer be felt through the abdomen. Full return to its original pear size takes about six weeks, though you won’t feel any of this happening. The cramping sensations some people notice in the early postpartum days, especially during breastfeeding, are the uterine muscles contracting as part of this process.