Pregnancy Week 30: What to Expect — Baby Size, Symptoms & Tips

Week 30 marks a genuinely exciting neurological moment: your baby's brain is actively forming its characteristic folds and wrinkles. These gyri and sulci — the ridges and grooves of the cerebral cortex — are the result of rapid brain tissue growth against a confined space, and they dramatically expand the brain's functional surface area. More wrinkles means more thinking power, eventually.

You're ten weeks from your due date. The home stretch feels real now.

Use our Due Date Calculator to count down to your estimated arrival.

Key Takeaways

• Your baby is large-cabbage-sized at about 39.9 cm and 1.3 kilograms — ten weeks from your due date
• Brain gyrification is accelerating: the cortical folds tripling the brain's functional surface area
• Lanugo (the fine body hair) is beginning to shed and be replaced by vernix and fat deposits
• Sleep becomes increasingly difficult at 30 weeks — a U-shaped pregnancy pillow is one of the most effective solutions
• Know the signs of preeclampsia by heart: severe headache, visual changes, sudden facial/hand swelling, upper right abdominal pain

Your Baby This Week

Size: Large cabbage — about 39.9 cm (head to toe)

Weight: About 1.3 kilograms

Your baby is over 1.3 kilos and growing fast. Here's what's most notable:

• Brain gyrification is accelerating. The smooth brain of earlier pregnancy is now actively developing its characteristic ridged surface. Sulci (grooves) and gyri (folds) form as the rapidly proliferating neurons push against the skull. This process increases the surface area of the cerebral cortex by a factor of three compared to a smooth brain, enabling vastly more neural connections.
• Bone marrow is fully functional. Red blood cell production is entirely handled by the marrow now, maintaining the high red blood cell levels needed to deliver oxygen to the rapidly developing brain and organs.
• Lanugo is beginning to disappear. The fine downy hair that has covered the baby's body for months starts shedding around now. It's often swallowed and becomes part of the meconium.
• Toenails and fingernails are growing. By now they extend close to the tips of the digits, and some babies are born needing a nail trim.
• The baby is filling out. Fat stores are building steadily. The characteristic dimples at the knees and elbows are beginning to appear as subcutaneous fat deposits fill in.
• Eyebrows are fully formed. Along with eyelashes, they give the face the complete look of a newborn.

Your Body This Week

At 30 weeks, you likely feel very pregnant. Here's what's typical:

• Significant difficulty sleeping. Between a large belly, back pain, heartburn, and frequent urination, good sleep is increasingly hard to come by. A U-shaped pregnancy pillow, elevating the head of your mattress slightly to reduce heartburn, and a consistent sleep schedule all help. Rest when you can, even if it's not overnight sleep.
• Shortness of breath. The uterus is now pressing significantly into the diaphragm's space. Mild breathlessness with exertion is expected. Practicing good posture — sitting tall, avoiding slouching — helps create more room.
• Braxton Hicks contractions. These may be more frequent and perhaps more intense. They're still harmless, but the increase in frequency is your body preparing.
• Pelvic girdle pain. The relaxing of pelvic ligaments can cause pain in the pubic area, hips, and buttocks. A physiotherapist experienced in pelvic health can provide specific exercises and support recommendations.
• The baby's position. Many babies begin settling into a head-down (cephalic) position around 28-32 weeks, though this isn't finalized until closer to birth. If your baby is still breech, there's still time for them to turn.
• Emotional readiness (and occasional unreadiness). Mixed feelings about the birth and the massive change ahead are completely normal. Being honest about fear or uncertainty — with your provider, your partner, or a therapist — is far healthier than suppressing it.

Tips for Week 30

1. Attend your antenatal appointments without fail. From 28 weeks, blood pressure is monitored closely for signs of preeclampsia. Missing appointments in the third trimester can mean missing the early warning signs of serious complications.

2. Research cord blood banking. If you're considering banking your baby's cord blood, you need to arrange this before birth — the window for collection is immediately at delivery. Research the options (public vs. private banking) and make a decision now if you're interested.

3. Start preparing siblings or pets. If this isn't your first baby, now is a good time to prepare older children for the arrival. If you have pets, gradual introduction to baby-related sounds and smells can help ease the transition.

4. Know the signs of preeclampsia by heart. Preeclampsia risk increases as pregnancy progresses and peaks in the third trimester. The signs: severe headache, visual changes, sudden swelling in the face or hands, pain in the upper right abdomen. These need same-day medical attention.

5. Have the postpartum conversation. Who will help in the first weeks? What does support look like for you? What are your expectations around visitors, breastfeeding, and sleep arrangements? These conversations are much easier now than in the fog of the newborn period.

When to Call Your Doctor

• Decreased or changed fetal movement. Do your daily kick count. Less than 10 movements in 2 hours at a typically active time warrants a call.
• Signs of preeclampsia: severe headache, blurred or changed vision, sudden swelling in face/hands, pain under the right ribs — get evaluated the same day
• Regular contractions before 37 weeks — even if they feel mild, rhythmic contractions need to be assessed
• Leaking fluid from the vagina — if your membranes have ruptured (water breaking), call immediately regardless of gestational age
• Persistent severe abdominal pain without contractions — can indicate placental abruption, which is an emergency

Frequently Asked Questions

How big is my baby at 30 weeks pregnant?

At 30 weeks, your baby measures about 39.9 cm (15.7 inches) from head to toe and weighs approximately 1.3 kilograms (2.9 lbs) — roughly the size of a large cabbage. You are ten weeks from your estimated due date, and your baby will continue gaining significant weight every week through to birth.

What is gyrification and when does it happen?

Gyrification is the process by which the brain develops its characteristic folds (gyri) and grooves (sulci). This happens because rapidly proliferating neurons push against the confined space of the skull. The result is a dramatically increased cortical surface area — up to three times larger than a smooth brain — which enables vastly more neural connections. The process begins in the second trimester and accelerates significantly through the third, making weeks 28–35 a particularly critical window for brain development.

What does cord blood banking involve and when do I need to decide?

Cord blood banking involves collecting stem cells from the umbilical cord blood immediately after delivery. The window for collection is very short — it must be arranged before birth. Public cord blood banks (where cord blood is donated for any patient in need) are free; private banks charge a collection and annual storage fee. If you are considering this, contact a provider or your hospital's maternity unit now to understand your options and register before your due date.

Is it normal for my baby to be in a breech position at 30 weeks?

Yes. Many babies are still in a breech (bottom-down) or transverse position at 30 weeks. Most babies turn to a head-down (cephalic) position on their own between 28 and 36 weeks. If your baby is still breech at 36 weeks, your provider will discuss options including external cephalic version (ECV) — a procedure to manually turn the baby. There is plenty of time for your baby to shift position naturally.

What are the signs of preeclampsia I should watch for at 30 weeks?

Preeclampsia risk increases through the third trimester. Know these warning signs by heart: severe headache that doesn't respond to paracetamol, visual changes (blurred vision, floaters, light sensitivity), sudden significant swelling in the face or hands, and pain in the upper right side of the abdomen under the ribs. Any combination of these symptoms requires same-day medical evaluation. ACOG recommends contacting your provider or going to the nearest maternity unit without waiting for your next scheduled appointment.

Related Tools & Articles

• Due Date Calculator — Your countdown to the due date
• Contraction Timer — For when the real thing starts
• Hospital Bag Checklist — Pack it this week if you haven't
• Pregnancy Week-by-Week Overview — Full timeline
• Milestone Tracker — Track your baby's development

Sources

• ACOG — Preeclampsia and High Blood Pressure During Pregnancy
• ACOG — Antepartum Fetal Surveillance
• Mayo Clinic — Fetal Development: The Third Trimester
• WHO — WHO Recommendations on Antenatal Care

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