37 Weeks Pregnant: Baby Size, Symptoms & What to Expect
Your baby is about 19 inches long and the size of a bunch of Swiss chard — considered early term and practicing breathing. Labor could start any day now.
By TeachToddler Editorial Team · Updated April 11, 2026 · Pregnancy
👶 Your Baby's Development at 37 Weeks
At 37 weeks, your baby is about 19 inches long from head to heel and weighs roughly 6.3 pounds — approximately the size of a bunch of Swiss chard. Your baby is now classified as "early term" and would likely thrive if born this week, though every additional day in the womb supports further development.
- Practicing breathing: Your baby is performing rhythmic breathing movements, inhaling and exhaling amniotic fluid up to 40 times per minute. This strengthens the diaphragm and prepares the lungs for their first real breath
- Brain development: The brain has been growing rapidly — it's about 30% larger than it was at 35 weeks. Neural connections are forming at a staggering rate, and the brain will continue developing well after birth
- Fat accumulation: Your baby continues to gain about half a pound per week, adding insulating fat. At birth, about 15% of your baby's weight will be body fat
- Immune system: Antibodies are actively crossing the placenta from you to your baby, building passive immunity that will protect your newborn for the first several months
- Digestive system ready: The intestines contain meconium — a dark, tar-like substance made of amniotic fluid, bile, and shed cells — that will be your baby's first bowel movement
- Firm grasp: Your baby can grip tightly and has developed coordination of sucking, swallowing, and breathing — essential for feeding after birth
- Head position: Most babies are head-down (cephalic presentation) by now. About 3–4% remain breech; your provider will discuss options like external cephalic version (ECV) if needed
🤰 Your Body at 37 Weeks
At 37 weeks, you're likely carrying 25–35 pounds of extra weight, your uterus has expanded to about 1,000 times its pre-pregnancy volume, and your body is showing signs that labor is on the horizon. Weekly prenatal visits begin now.
- Lightning crotch: Sudden, sharp, shooting pains in the pelvis, vagina, or rectum caused by the baby's head pressing on nerves in the cervix. Lasts only seconds but can take your breath away. Changing positions helps
- Mucus plug: You may notice a thick, jelly-like discharge — clear, white, or tinged with pink or brown. This is the mucus plug that has sealed your cervix throughout pregnancy. Its loss (sometimes called "bloody show") means your cervix is beginning to change, but labor may still be days or weeks away
- Increased pelvic pressure: As the baby's head settles deep in the pelvis, you'll feel heavy pressure on your bladder, pelvis, and perineum. Walking may feel like waddling
- Nesting overdrive: The urge to organize, clean, and prepare may intensify. Channel this energy productively but rest when you need to — you'll need your strength for labor
- Braxton Hicks ramping up: Practice contractions may become more frequent and more intense. They're still irregular and not increasing in strength — that's how you know they're not the real thing
- Diarrhea or loose stools: Prostaglandins, hormones that ripen the cervix, can also affect the bowels. Frequent loose stools can be a pre-labor sign
Know When to Go: Use the 5-1-1 rule — contractions 5 minutes apart, lasting 1 minute each, for 1 hour. Go immediately if: your water breaks, you have heavy bleeding, the baby stops moving, or you have severe headache with vision changes. If this is your second (or more) baby, head in sooner — subsequent labors often progress faster. When in doubt, call your provider.
🩺 Cervical Checks and Appointments
Starting at 37 weeks, your provider may begin cervical exams at your weekly appointments to check for signs that your body is preparing for labor. Here's what they're measuring.
- Dilation: How open the cervix is, measured in centimeters from 0 (closed) to 10 (fully dilated). Many women walk around 1–3 cm dilated for weeks before labor
- Effacement: How thin the cervix is, expressed as a percentage. Fully effaced (100%) means the cervix has thinned completely in preparation for delivery
- Station: How far the baby's head has descended into the pelvis, measured from -3 (high) to +3 (crowning). Zero station means the head is at the level of the ischial spines
- What these numbers mean: Dilation and effacement don't predict when labor will start. Some women are 3 cm dilated for weeks; others go from 0 to delivery in hours. These checks are optional — you can decline them
- GBS results: If you tested positive for Group B Strep last week, your chart is now flagged so you'll receive IV antibiotics when you arrive at the hospital in labor
🧘 Labor Positions and Comfort Techniques
Knowing different labor positions and pain management techniques before labor begins helps you feel more prepared and in control. Practice these now with your partner or support person.
- Upright positions: Standing, walking, swaying, slow dancing with your partner — gravity helps the baby descend and can shorten labor
- Hands and knees: Relieves back labor (when baby is posterior/sunny-side up) and takes pressure off the spine. Can also help a posterior baby rotate
- Birth ball: Sitting and rocking on a birth ball opens the pelvis, provides gentle movement, and can be very comfortable during early labor
- Counter-pressure: Have your partner press firmly on your lower back with a fist or tennis ball during contractions to relieve back labor pain
- Water therapy: A warm shower directed at your lower back or immersion in a tub can significantly reduce pain perception. Many hospitals have labor tubs
- Breathing techniques: Slow, deep breathing (in through the nose, out through the mouth) helps you stay calm and oxygenated. Practice now so it becomes automatic
✅ Last-Minute Prep Checklist
With your due date just 3 weeks away, make sure these final preparations are handled so you can focus on labor and your new baby.
- Car seat installed: Install the infant car seat and have it inspected at a certified inspection station (many fire departments offer this for free)
- Pediatrician selected: Choose a pediatrician and confirm they're accepting new patients. Your baby will be seen within 3–5 days of discharge
- Postpartum plan: Line up help for the first few weeks — a partner's leave, family visits, a postpartum doula, or a meal train
- Work/leave details: Confirm maternity and paternity leave start dates, out-of-office messages, and handoff plans
- Phone tree: Decide who gets notified about the birth and when. Some parents prefer to wait until after the golden hour for bonding before making calls
- Freezer meals: Stock up on easy-to-reheat meals — soups, casseroles, burritos, and lactation-friendly snacks
🔮 Looking Ahead to Week 38
Next week, your baby will be about 19.5 inches and 6.8 pounds. The brain and lungs continue their final maturation. You're now within the window where labor could begin at any time and your baby would be considered full term at 39 weeks.
- Pay attention to changes in your body — increased discharge, more frequent Braxton Hicks, loose stools, and a burst of energy can all be pre-labor signs
- Continue kick counts — 10 movements in 2 hours. Report any significant decrease in movement immediately
- Rest as much as possible. Sleep may be difficult, but even lying on your side with your eyes closed helps conserve energy
- Stay close to home and keep your phone charged. Make sure you and your support person know the fastest route to the hospital at different times of day