At 39 weeks, you’re officially full term, and your baby could arrive any day. Your body is running through its final preparations for labor, which means new aches, strange sensations, and a lot of wondering whether every twinge is “the real thing.” Here’s what’s actually happening this week, from your baby’s last growth spurt to the signals your body sends as labor approaches.
Your Baby’s Size and Development
By 39 weeks, your baby weighs roughly 7 to 7.5 pounds and measures about 20 inches from head to toe (around 14 inches crown to rump). Healthy babies vary quite a bit, though, so your provider may estimate a weight a pound or more in either direction.
What matters most at this stage is what’s happening inside. Half of the brain’s outer layer (the part responsible for thinking, learning, and processing senses) develops in the last six weeks of pregnancy. Your baby is still actively building neural connections right now. The lungs are also putting finishing touches on their ability to function independently, producing the slippery substance that keeps air sacs from collapsing with each breath. Even babies whose lungs test as “mature” before 39 weeks have higher rates of breathing problems after birth compared to those who reach this milestone, which is one reason providers avoid scheduling deliveries earlier without a medical reason.
You may notice that your baby’s movements feel different. Instead of sharp kicks, you’re more likely to feel rolls, stretches, and shifting as your baby runs out of room. This is normal, but the total number of movements you feel each day should stay about the same.
Common Physical Symptoms
The final stretch of pregnancy brings a cluster of symptoms that can range from mildly annoying to genuinely uncomfortable. Most are signs that your body is doing exactly what it should.
Pelvic pressure. As your baby drops lower into your pelvis (a process called “lightening”), you may feel heavy pressure deep in your pelvis or low back. Some people notice this weeks before labor, while others don’t experience it until labor itself begins. On the bright side, once the baby drops, breathing often gets easier because there’s less pressure on your lungs.
Lightning crotch. This is exactly as fun as it sounds. Sharp, shooting nerve pain in your pelvis or groin happens when your baby’s head presses on nerves. It comes in sudden jolts and usually passes quickly.
Vaginal discharge changes. Your discharge may become thicker, stickier, or slightly pink. You might also lose your mucus plug, which looks like a glob of thick, jelly-like discharge, sometimes streaked with blood. Losing it can happen days or even weeks before labor starts, so it’s not a reliable countdown clock on its own.
Braxton Hicks contractions. These practice contractions tighten your belly and may feel like mild cramping. They come and go without a pattern and typically stop when you change positions, walk around, or drink water.
Trouble sleeping, back pain, and general exhaustion. Between the weight, the bathroom trips, and the difficulty finding a comfortable position, solid sleep is hard to come by. This is one of the most universally reported frustrations at 39 weeks.
How to Tell Real Labor From False Alarms
The single most reliable difference between Braxton Hicks and true labor contractions is pattern. Braxton Hicks are irregular. They might show up a few times in an hour, then disappear for the rest of the day. True labor contractions get longer, stronger, and closer together over time, and nothing you do makes them stop. Changing positions, resting, or drinking water won’t slow them down.
Braxton Hicks also tend to be felt mainly in the front of your belly, like a tightening or hardening. Real contractions often start in your lower back and wrap around to the front, building in intensity like a wave.
A widely used guideline for when to head to the hospital is the 5-1-1 rule: contractions coming every five minutes, each lasting at least one minute, and the pattern holding steady for at least one hour. Your provider may give you slightly different instructions depending on your situation (distance from the hospital, whether this is your first baby, or specific risk factors), so it’s worth confirming their preference at your next visit.
Bloody show, a small amount of blood-tinged mucus, means your cervix is starting to open. For some people, labor follows within hours. For others, it’s still days away. If you soak through a pad with bright red blood, that’s different and worth calling about right away.
What Happens at Your Prenatal Visit
At 39 weeks, you’re likely seeing your provider weekly. A typical visit includes checking your blood pressure, measuring your belly, and listening to the baby’s heartbeat. Your provider may offer a cervical exam to check how things are progressing, though this is optional and you can decline it.
During a cervical exam, your provider checks several things: how far your cervix has opened (dilation), how thin it’s become (effacement), and how low the baby’s head has moved into your pelvis (station). Together, these factors make up what’s called a Bishop score, which helps predict how ready your body is for labor. It’s worth knowing that being a few centimeters dilated doesn’t necessarily mean labor is imminent. Some people walk around at 2 or 3 centimeters for weeks, while others go from zero to active labor in a matter of hours.
Induction and Membrane Sweeping
Your provider may bring up induction at 39 weeks, especially if this is your first pregnancy. A large clinical trial (the ARRIVE trial) found that first-time mothers who were induced at 39 weeks had an 18.6% cesarean rate compared to 22.2% among those who waited for labor to start on its own. That’s a meaningful reduction in surgical delivery, and it’s changed how many providers approach the conversation. Induction at 39 weeks is now considered a reasonable option for low-risk first pregnancies, not just something reserved for medical complications.
A membrane sweep is a less intensive option your provider might offer. During a cervical exam, they separate the membranes of the amniotic sac from the cervix with a finger. It can be uncomfortable. Research shows that a single sweep at 39 weeks doesn’t significantly increase the chance of delivering within the next week (about 38% delivered within a week whether they had the sweep or not). However, sweeping does reduce the likelihood of going past 41 weeks. It’s a nudge, not a guarantee.
Monitoring Your Baby’s Movement
Kick counts remain important at 39 weeks. The standard recommendation is to feel 10 movements (kicks, rolls, flutters, or stretches) within two hours. Most people reach 10 well within an hour once they sit quietly and pay attention. Pick a time when your baby is usually active, often after a meal, and count until you hit 10.
Because your baby has less room now, the type of movement shifts. You’ll feel more rolling and pushing than the dramatic kicks you noticed earlier. That’s completely normal. What you’re watching for is a noticeable drop in the overall amount of movement compared to what’s been typical for your baby. If you don’t reach 10 movements in two hours, or if something feels off, contact your provider.
Practical Things to Have Ready
If you haven’t already, this is a good week to finalize the logistics. Your hospital bag should be packed and easy to grab. Key items include your ID and insurance information, a phone charger, comfortable clothes for after delivery, and a going-home outfit for the baby (newborn size, since most babies don’t fit 0-3 month clothes right away).
Make sure your car seat is installed. Many fire stations and hospitals offer free installation checks if you’re unsure about the setup. Know your route to the hospital or birth center and have a backup plan for getting there if your partner or planned driver isn’t available.
It also helps to have a few meals in the freezer, a plan for pet care or older children, and your provider’s after-hours phone number saved in your phone. At 39 weeks, labor can start at any time of day, and the less you have to figure out in the moment, the calmer the experience will feel.