At five months pregnant (around 20 weeks), your baby measures roughly 6.3 inches (16 cm) from head to bottom and weighs about 11 ounces (320 grams). That’s about the length of a banana and just under three-quarters of a pound. This is the halfway point of pregnancy, and your baby has grown from a cluster of cells to a fully formed, actively moving little person with working organs and sharpening senses.
Size and Proportions at 20 Weeks
The 6.3-inch measurement is taken from the crown of the head to the rump, which is the standard way fetal length is tracked through mid-pregnancy. If you measured from head to heel, with the legs extended, the total length would be closer to 10 inches. The legs are still tucked up against the body most of the time, so crown-to-rump gives a more consistent number.
During an ultrasound at this stage, your provider measures specific body parts to check that growth is on track. Two key measurements are the head diameter, which averages about 4.9 cm (just under 2 inches) across, and the thigh bone length, which averages 3.2 cm (about 1.25 inches). These numbers help confirm gestational age and flag any growth concerns early.
What Your Baby Looks Like Now
At five months, your baby has fully formed fingers and toes, distinct facial features, and eyelids that are still fused shut. The skin is thin and translucent, with blood vessels visible beneath it. A waxy, white coating called vernix covers the skin, protecting it from constant exposure to amniotic fluid. Fine, soft hair called lanugo grows over the body, helping the vernix stick in place. Both will mostly disappear before birth.
The arms and legs are now proportional to the rest of the body, which wasn’t the case earlier in pregnancy when the head was oversized relative to everything else. Your baby’s muscles are getting stronger, and there’s still plenty of room in the uterus to stretch, roll, and kick freely.
Movement You Can Feel
Five months is when most pregnant people first feel their baby move, a milestone called quickening. It typically happens between 16 and 20 weeks, though first-time mothers often notice it closer to the 20-week mark. The sensations are subtle at this stage. People describe them as fluttering, tiny bubbles popping, light tapping, or small muscle spasms. Nothing like the dramatic kicks that come later.
Because the baby is still small, movements come and go unpredictably. You might feel something one day and then nothing for a day or two. That’s normal at this point. By 24 weeks, movement patterns become more consistent and noticeable. For now, any fluttering you pick up on is a bonus, not something to track closely.
Hearing Begins to Develop
Around 20 weeks, your baby can begin to hear sounds from outside the womb. The amniotic fluid and surrounding tissue muffle most noise, so what reaches the baby is limited to low-frequency sounds: your heartbeat, the rhythm of your breathing, the deep tones of voices. Higher-pitched sounds are filtered out almost entirely.
This limited sound exposure appears to be by design. Research from MIT suggests that the muffled, low-frequency input a fetus receives is actually beneficial for the developing auditory system. Rather than being a limitation, the restricted sound environment helps the hearing pathways in the brain wire themselves correctly before the baby is born into a world of full, complex noise.
How Your Body Reflects the Growth
At 20 weeks, the top of your uterus reaches your belly button. From this point forward, your provider may start measuring fundal height, the distance in centimeters from your pubic bone to the top of the uterus. The rule of thumb is simple: the measurement in centimeters should roughly match your week of pregnancy, give or take 2 cm. So at 20 weeks, a fundal height of 18 to 22 cm is considered normal.
This is also around the time many people have their anatomy scan, a detailed ultrasound that checks the baby’s organs, spine, brain, and limbs. It’s the appointment where the baby’s size is formally assessed and where you can often learn the sex if you want to know.
Week-by-Week Growth Through Month Five
Month five spans roughly weeks 17 through 20, and growth accelerates noticeably during this stretch. At the start of the month, your baby weighs around 5 to 6 ounces. By week 20, that nearly doubles to 11 ounces. Length increases more gradually, from about 5 inches crown-to-rump to 6.3 inches.
This is a period of rapid weight gain relative to earlier months. During the first trimester, most development was structural: building organs, forming limbs, establishing the nervous system. Now the baby is filling out, adding fat and muscle. That trend continues and intensifies through the third trimester, when your baby will gain roughly half a pound per week in the final stretch before birth.
Comparing Size to Everyday Objects
Visualizing 6.3 inches and 11 ounces can be tricky in the abstract. Your baby at five months is about the size of a banana or a large mango. It weighs roughly as much as a can of soda or a baseball. The head is about the width of a lime. These comparisons aren’t precise, but they give you a realistic sense of scale. Your baby is substantial enough to make its presence felt, literally, but still small enough to somersault freely inside the uterus with room to spare.