At five months pregnant (roughly weeks 18 through 22), your baby is about 6⅓ inches long from head to rump and weighs around 11 ounces, or about the size of a small banana. Your uterus has grown enough to reach your belly button, and most people have a clearly visible bump by this point. But “how big” means different things depending on whether you’re asking about the baby, your belly, or your overall weight gain, so let’s break down all three.
How Big Is the Baby at 5 Months
By week 20, the midpoint of a full-term pregnancy, the baby measures roughly 6⅓ inches (about 160 millimeters) from the top of the head to the bottom of the spine, and weighs approximately 11 ounces (320 grams). That head-to-rump measurement doesn’t include the legs, which are curled up. If you stretched the baby out fully, the total length would be closer to 10 inches.
Fruit comparisons are a popular way to picture this: at 19 weeks, your baby is roughly the size of an heirloom tomato. By the end of the fifth month, think closer to a small mango. The baby is growing fast during this stretch, adding several ounces per week, and their proportions are shifting. Earlier in pregnancy the head was nearly half the body’s total length. By five months, the limbs have caught up significantly, and the body looks more like a newborn in miniature.
How Big Your Belly Gets
Your uterus reaches your belly button at about 20 weeks. Before pregnancy it sat deep in the pelvis and weighed only a few ounces. By five months it’s the size of a cantaloupe and has risen high enough to push your abdominal wall forward, creating the bump most people associate with mid-pregnancy.
Providers often measure this growth with a tape from your pubic bone to the top of the uterus. This measurement, called fundal height, roughly matches your week count in centimeters, plus or minus two. So at 20 weeks, a measurement between 18 and 22 centimeters is considered normal.
That said, bump size varies enormously from person to person. Several factors play a role:
- Previous pregnancies. If you’ve been pregnant before, your abdominal muscles are more relaxed and you’ll typically show earlier and look bigger at the same stage.
- Height and torso length. Taller people with longer torsos have more room for the uterus to expand upward before it pushes outward, so they often show later.
- Abdominal muscle tone. Stronger core muscles can hold the uterus closer to the spine for longer, making the bump less prominent in early months.
- Weight and body composition. Your starting weight and how you carry it affects how visible the bump is to others.
If your bump looks smaller or bigger than someone else at the same stage, that’s almost always normal. Your provider is tracking the baby’s actual growth on ultrasound, which is a far more reliable measure than belly size.
Weight Gain by 5 Months
During the second trimester, most people gain about 1 pound per week. The typical range is 0.7 to 1.4 pounds per week, so there’s a wide window of normal. By the 20-week mark, a total gain of around 8 to 15 pounds from your pre-pregnancy weight is common for someone who started at a normal BMI, though the exact target depends on your starting weight.
That weight isn’t all baby. At five months the baby accounts for less than a pound of it. The rest comes from the growing placenta, increased blood volume (you have about 50% more blood by mid-pregnancy), amniotic fluid, breast tissue changes, and the extra fat stores your body is building to support the rest of pregnancy and breastfeeding. Your uterus alone has gained significant weight from its muscular growth.
What You Might Feel at This Size
Five months is when many people first feel the baby move. Early movements feel like flutters, bubbles, or light tapping. If this is your first pregnancy, you may not recognize them until closer to 20 or 22 weeks. Second-time parents often notice them a few weeks earlier because they know what to expect.
The expanding uterus can also create some new physical sensations. Round ligament pain, a sharp or pulling feeling on the sides of your lower belly, is common as the ligaments stretching to support the uterus get tugged during quick movements. You may notice your center of gravity shifting, making you feel slightly less balanced than usual. Some people start experiencing mild lower back discomfort as the bump changes their posture.
This is also right around the time of the mid-pregnancy anatomy scan, typically scheduled between weeks 18 and 22. That ultrasound gives you the most detailed look at the baby’s size, organ development, and growth trajectory, and it’s often the appointment where parents learn the sex if they want to know.