Five months pregnant falls around weeks 17 through 20 of pregnancy. The reason this isn’t a clean, obvious number is that pregnancy months and calendar months don’t line up neatly. A full-term pregnancy lasts 40 weeks, which is actually closer to 10 months than nine, and the count starts from the first day of your last menstrual period rather than from conception.
Why Weeks and Months Don’t Match Up
Most people think of pregnancy as lasting nine months, but the math tells a different story. Pregnancy is dated from the first day of your last period, not from when you actually conceived (which typically happens about two weeks later). That pushes the total timeline to 40 weeks, or roughly 10 lunar months of four weeks each.
Calendar months, though, aren’t exactly four weeks. Most are 30 or 31 days, which means they contain about 4.3 weeks. So when you try to convert weeks into months, the numbers drift depending on which system you use. Your doctor will almost always refer to your pregnancy in weeks because it’s more precise. If someone asks how far along you are and you say “20 weeks,” that’s a much clearer answer than “five months,” which could mean different things to different people.
Where Month Five Sits in the Bigger Picture
The fifth month lands squarely in the second trimester, which runs from week 13 through week 26. By week 20, you’re at the exact midpoint of pregnancy. This is often when things start to feel more real: your belly is visibly growing, and around the 20-week mark, the top of your uterus reaches your belly button. From this point on, the distance from your pubic bone to the top of your uterus (measured in centimeters) roughly matches your week of pregnancy, give or take 2 centimeters.
What’s Happening With Your Baby
A lot changes between weeks 17 and 20. Around week 17, the baby’s skin is still thin but begins building up a layer of fat underneath. A waxy, white coating called vernix forms over the skin to protect it from constant exposure to amniotic fluid. By week 18, the baby starts cycling between sleep and wakefulness, and loud noises can actually wake them up.
By week 20, the baby measures about 6⅓ inches from the top of the head to the rump and weighs around 11 ounces. That’s roughly the length of a banana. The limbs are well-formed, and movements are becoming coordinated enough that you can feel them.
What You Might Be Feeling
The fifth month is when many people feel their baby move for the first time. If this is your first pregnancy, those initial movements (sometimes called quickening) can feel like fluttering, bubbles, or a light tapping. People who’ve been pregnant before often recognize the sensation a few weeks earlier.
You may also start noticing Braxton Hicks contractions, a mild tightening across your belly that comes and goes. These tend to show up in the afternoon or evening, especially after physical activity. They’re harmless and irregular. If they start coming at regular intervals and getting stronger, that’s worth a call to your provider since it could signal preterm labor.
Weight gain by this point varies, but the general pattern is 1 to 4 pounds in the first trimester, then about a pound per week through the rest of pregnancy. So by week 20, many people have gained somewhere in the range of 8 to 12 pounds total, though individual variation is wide.
The 20-Week Anatomy Scan
One of the biggest milestones at five months is the anatomy ultrasound, typically scheduled around week 20. This is the most detailed ultrasound of the entire pregnancy. A technician takes images and measurements of the baby’s heart, brain, spine, kidneys, lungs, stomach, limbs, and facial features. They also record the heart rate, check blood flow through the umbilical cord, measure amniotic fluid levels, and evaluate the position of the placenta.
This is also the appointment where you can find out the baby’s sex, if you want to know. The scan usually takes 30 to 45 minutes, and while it’s thorough, it’s painless. If the baby isn’t in an ideal position, the technician may ask you to walk around or shift positions so they can get the views they need.