Pregnancy Week 29: Baby's Bones Fully Formed

You're 29 weeks pregnant, which means you've officially entered the "the third trimester is real" phase. The bump is unmistakable, strangers have opinions, and your favorite jeans are a distant memory. Meanwhile, inside, something quietly extraordinary is happening — your baby's bones are fully formed, their brain is firing new connections by the second, and they're putting on the layers of fat that will keep them warm on the outside.

This week's guide covers what's happening with baby, how your body is adapting (and complaining), what to eat, what to watch for, how to count kicks properly, safe movement, and the checklist stuff that starts to feel urgent — hospital bag, car seat, birth plan. The tone is that of a slightly-caffeinated friend who happens to have read the actual research.

One thing up front: this article is educational, not medical advice. Every pregnancy is its own thing, and your provider knows your history in a way we can't. We're the team behind Vyve, a private AI pregnancy tracker with kick counter and contraction timer built in — so consider the source — but nothing here replaces a real appointment.

Your baby at 29 weeks

The headline this week: your baby's bones are fully formed. That doesn't mean they're finished — the skeleton will keep hardening (a process called ossification) all the way through birth and into childhood — but the framework is complete. Every rib, every finger bone, every tiny vertebra is in place, and baby is now busy stockpiling calcium to strengthen them.

The brain is having an even more dramatic week. Neurons are forming and connecting at an astonishing rate, and the surface of the brain — which was smooth just weeks ago — is starting to develop the wrinkles and grooves that give it that classic walnut look. Those grooves aren't cosmetic; they let the brain pack more surface area into the same space, which is roughly the neurological equivalent of buying a bigger hard drive.

Elsewhere, the lungs are still practicing — baby "breathes" amniotic fluid in and out, rehearsing for the first real breath. The eyes can move now, and there's evidence that babies at this stage respond to light passing through the abdominal wall. Muscles are getting stronger, which is why the flutters of a few weeks ago now feel like proper jabs and rolls. And baby is putting on white fat — the kind that provides insulation and energy, rounding out those cheeks and thighs.

How big is baby this week?

At 29 weeks, baby is roughly the size of a butternut squash — about 15 to 16 inches (38 to 40 cm) from head to heel and around 2.5 to 3 pounds (1.15 to 1.35 kg). If produce metaphors aren't your thing, picture a small bag of sugar with limbs.

Growth accelerates from here. Baby will roughly triple in weight between now and delivery, which is exactly why the coming weeks can feel like your body is running on hard mode. If you want a clearer sense of your timeline, our due date calculator will map your remaining weeks and give you a realistic view of what's ahead.

Your body at 29 weeks

Your uterus is now around 3 to 4 inches above your belly button, which means it's crowding just about every organ you own. The stomach is squished (hello, heartburn), the bladder is under new management (hello, hourly bathroom trips), the diaphragm is getting nudged upward (hello, being winded after climbing four stairs). This is all completely normal, if occasionally undignified.

Your blood volume is up about 40 to 50 percent from pre-pregnancy — an enormous cardiovascular effort — and your heart is pumping harder to move all of it. This is why you might feel dizzy standing up too fast, and why iron matters so much this trimester (more on that in a moment). Hormones are also relaxing your joints and ligaments to prepare for birth, which is helpful when you're delivering a baby and slightly less helpful when you're trying to walk downstairs without your hips complaining.

Common symptoms this week

Not everyone gets everything on this list — pregnancies vary as much as people do — but week 29 tends to bring a familiar cast of characters:

• Fatigue that hits different. Not the sleepy tiredness of first trimester, more of a bone-deep "I could nap standing up" feeling. Your body is doing enormous work.
• Braxton Hicks contractions. Practice contractions that come and go, don't build a pattern, and usually ease with rest, water or a change in position. Not labor, just your uterus rehearsing.
• Back pain and pelvic pain. A heavier bump plus relaxed ligaments equals a body that aches in new places. Pelvic girdle pain in particular is real and worth mentioning to your provider.
• Swelling in feet, ankles and hands — usually mild and worse by evening. Sudden, severe or one-sided swelling is different and needs a call.
• Heartburn and reflux. Progesterone plus a crowded stomach. Smaller meals, sitting up after eating, and avoiding trigger foods help most people.
• Sleep chaos. Getting comfortable takes engineering — pillow between the knees, pillow behind the back, pillow under the bump. Sleeping on your left side is generally recommended in the third trimester as it optimizes blood flow.
• Shortness of breath from the uterus pressing up. It eases once baby drops closer to birth.
• Leg cramps, especially at night. Hydration, gentle stretching, and getting enough calcium and magnesium can help.
• Colostrum leaking from the breasts for some people. Also normal, though not universal — its absence doesn't mean anything is wrong.

If your symptom list this trimester feels wildly different from the early signs of pregnancy you had months ago, that's expected — first-trimester and third-trimester pregnancies are basically two different projects.

Nutrition: iron takes center stage

Third-trimester nutrition isn't about eating for two — it's about eating well for one and giving baby the raw materials for a huge growth spurt. Your calorie needs are only modestly up (roughly 300–450 extra calories a day, less than most people think), but a few nutrients deserve special attention around week 29.

Iron is the big one. Your blood volume is way up, baby is stockpiling iron for the first months of life, and iron-deficiency anemia is genuinely common in the third trimester. Iron-rich foods include lean red meat, chicken, fish, lentils, chickpeas, spinach, tofu and fortified cereals. Pairing them with vitamin C — a squeeze of lemon on your lentils, orange slices with fortified cereal — significantly boosts absorption. Coffee and tea, on the other hand, can interfere with iron absorption, so it's worth spacing them from iron-heavy meals.

Protein supports baby's rapid tissue growth — aim for a source at every meal (eggs, dairy, beans, lean meats, fish that's safe in pregnancy). Calcium and vitamin D support those newly-formed bones (dairy, fortified plant milks, leafy greens, sunshine when you can). Fiber and fluids tackle the constipation and swelling that plague this trimester — think fruits, vegetables, whole grains, and roughly 8–10 cups of water a day.

Small meals often beat big ones now. Your stomach is squished, heartburn is opportunistic, and grazing five or six times a day tends to feel better than three heavy plates.

Kick counts and fetal movement

By 29 weeks, fetal movements should be well established and — critically — following a pattern that you recognize. Not a textbook pattern. Yours. Your baby's active times, their quiet naps, their preferred kicks-in-the-ribs move — that's the data that matters.

The widely used rule of thumb is 10 movements in 2 hours. Pick a time when baby is usually active (often after meals or in the evening), sit quietly or lie on your side, and count. A kick, roll, jab or hiccup all count as one movement. Most people reach 10 well within an hour. If you don't, try eating or drinking something cold, then count again. If movements are still low compared to your normal pattern, call your provider — day or night. Providers would always rather hear from you and reassure you than have you wait.

A common myth: "babies slow down at the end of pregnancy because they run out of room." They don't. The type of movement may change — less swimming, more purposeful pushes and stretches — but the frequency should stay consistent. A real decrease in movement is one of the most important warning signs in the third trimester, and it should never be dismissed.

You don't need to hit a magic number every day. You need to know your baby's normal — and to trust yourself when it drops.

Safe movement in the third trimester

Movement in the third trimester is genuinely helpful — for mood, sleep, circulation, back pain and even birth preparation — but the pace and shape of it change. This is not the trimester for personal bests. It's the trimester for gentle, consistent, feel-good movement.

Well-tolerated options at 29 weeks include walking (nothing fancier needed), prenatal yoga (great for hips, breathing and calm), swimming and water aerobics (blissfully weightless when your back hurts), stationary cycling, and pelvic floor exercises (Kegels — worth their weight in gold now and after birth). Avoid contact sports, anything with fall risk, lying flat on your back for extended stretches, and pushing yourself to breathlessness.

Listen to your body loudly. Stop if you feel dizzy, breathless in a way that doesn't recover, cramping, contractions, bleeding, or fluid leaking. Hydrate. Wear supportive shoes. And when in doubt, a walk always counts.

Your 29-week checklist

Some of these are urgent, some are just useful — but as a group, they turn "I should probably do that" into "already done." Small wins now save huge headaches later.

• Start (or update) your hospital bag. Basics: ID, insurance card, phone charger, comfy going-home outfit, toiletries, snacks, going-home outfit for baby, nursing bras or comfortable pajamas, and a small pillow if you're picky.
• Sketch a birth plan draft. It's a wish list, not a contract — but writing it forces useful conversations with your partner and provider about pain relief, positions, delayed cord clamping, skin-to-skin, and who's in the room.
• Book a car seat install check. Many fire stations and hospitals do this free. A correctly installed seat is one of the most protective things you'll ever do for your baby.
• Choose a pediatrician. Interview one or two — you'll want a name to give the hospital.
• Book or confirm your glucose tolerance test if you haven't already (usually done between 24 and 28 weeks, sometimes slightly later).
• Sign up for a childbirth class if you haven't yet — many are 4–6 weeks long and start filling up around now.

When to call your provider

Being pregnant means constantly weighing "is this normal?" against "should I call?" The correct answer, honestly, is that if you're wondering, calling is fine. Providers deal with this every day and would much rather answer a low-stakes question than miss a real one. That said, these signs need a call the same day — or a trip to labor and delivery — without hesitation:

• Decreased fetal movement compared to your normal pattern.
• Any vaginal bleeding.
• A gush or steady trickle of clear fluid, which could mean your water has broken.
• Regular, painful contractions more than 4 in an hour before 37 weeks (possible preterm labor).
• Severe headache, especially with vision changes, spots or blurring.
• Sudden severe swelling of face and hands, or pain in the upper right belly — possible preeclampsia signs.
• Painful, red, swollen calf — possible blood clot.
• Fever above 100.4°F (38°C) or feeling seriously unwell.
• Persistent vomiting or inability to keep fluids down.

You are not being dramatic by calling. You are being appropriate.

Tracking week 29 with Vyve

Third trimester is when a good tracker starts pulling its weight. There's a lot to keep tabs on — kick counts, symptoms that come and go, contractions when they start, weight and blood pressure notes for appointments, all the small patterns your provider will ask about.

Vyve is a private AI pregnancy tracker with kick counter and contraction timer built in. Log kicks with a single tap, time contractions when they arrive, and note symptoms as they happen. Vyve learns your baby's pattern, flags meaningful changes rather than random noise, and exports a clean doctor-ready summary you can pull up at your next appointment. It runs on your device, your data doesn't get sold, and no one is going to email you baby-product ads because of it. For something this personal, that's the whole point.

If you're brand-new to cycle and pregnancy tracking overall, our AI period tracker guide and menstrual cycle phases primer are a decent post-pregnancy read-ahead too.

Frequently asked questions

How big is my baby at 29 weeks pregnant?

Roughly the size of a butternut squash — about 15 to 16 inches (38 to 40 cm) and 2.5 to 3 pounds (1.15 to 1.35 kg). Individual variation is normal at this stage, so a difference of a few ounces isn't cause for worry on its own.

What's happening with my baby at week 29?

Baby's bones are fully formed (though still hardening), the brain is developing its distinctive folds and firing new connections quickly, lungs continue to mature, muscles are stronger, eyes can respond to light through the belly, and layers of white fat are being laid down to help regulate temperature after birth.

How many kicks should I feel at 29 weeks?

The common guideline is 10 movements in 2 hours during an active time. What matters most is that you learn your baby's own pattern — their active hours, quiet hours and typical intensity — and call your provider if that pattern noticeably decreases.

Is fatigue normal at 29 weeks pregnant?

Very. Your blood volume is up around 40–50 percent, sleep is often interrupted, and iron levels can dip in the third trimester. Mention it to your provider if it feels crushing or comes with dizziness or breathlessness so iron and blood pressure can be checked.

What should I eat at 29 weeks pregnant?

Prioritize iron (with vitamin C to boost absorption), protein at every meal, calcium and vitamin D for bones, and plenty of fiber and fluids. Smaller, more frequent meals usually feel better than large ones as the uterus crowds the stomach.

Educational, not medical advice. Call your provider for concerns.