Pregnancy Week 38: What to Expect — Baby Size, Symptoms & Tips

Two weeks from your due date. Your baby is well past the 3-kilogram mark, and the final developmental polishing is happening inside: the brain and lungs are still refining themselves, even now. Week 38 is one of the most anticipatory weeks of pregnancy. You know it's soon. Your body knows it too.

Track your progress with our Due Date Calculator.

Key Takeaways

• Your baby weighs about 3.1 kg (leek-sized) and measures roughly 50 cm from head to toe
• Brain and lungs are still refining even now — every day between 37 and 40 weeks measurably improves outcomes
• Head is engaged in the pelvis; fingernails may already be past the fingertips
• Common symptoms: near-impossible sleep, cervical changes, prodromal labor, increased discharge, emotional intensity
• Action items: know the 5-1-1 rule, hospital bag in the car, eat protein-rich foods, review your birth plan

Your Baby This Week

Size: Leek — about 49.8 cm (head to toe)

Weight: About 3.1 kilograms

Your baby is looking very much like a newborn already. What's still happening:

• Brain development is ongoing. The brain is not finished — and won't be until your child is in their mid-twenties. But within the pregnancy window, the third trimester represents an enormous amount of neural wiring and myelination (the insulating of nerve pathways). Babies born at 39–40 weeks have measurably better cognitive and neurological outcomes than those born at 37–38 weeks. Every additional day counts.
• Lungs continue to mature. Surfactant production is at full capacity by 38 weeks for most babies, but the fine structure of the airways is still developing. The lungs won't fully mature until childhood.
• Meconium is in the intestines. Your baby will pass this dark, tarry first stool within the first day or two after birth. If meconium is present in the amniotic fluid before or during birth, your care team will watch carefully for any signs of aspiration.
• Lanugo is almost gone. The fine body hair that covered your baby has largely shed. You may see a small amount in skin creases at birth.
• Head is engaged. Most 38-week babies are head-down and low in the pelvis. You may feel increased pelvic pressure and the sensation of the baby pressing against your bladder constantly.
• Fingernails may need trimming. Babies born at full term sometimes come out with nails that have grown past the fingertips. Pack a baby nail file or infant mittens.

Your Body This Week

Week 38 is physically exhausting. That's the most accurate summary:

• Sleep is nearly impossible to achieve comfortably. Between the weight, the pelvic pressure, the frequent urination, and the general discomfort, most women at 38 weeks are getting fragmented sleep at best. This is genuinely hard. Do what you can: sleep in whatever position works, nap when possible, and accept that this period is temporary.
• Cervical changes are happening. Whether or not your provider is checking, your cervix is likely effacing (thinning) and beginning to dilate. These changes can happen over days or weeks, and dilation at 38 weeks does not predict whether you'll go into labor soon. Women can walk around at 2–3 cm for weeks, and others go from nothing to active labor in hours.
• Contractions are more frequent. Braxton Hicks are strong and frequent. You may also be experiencing prodromal labor — contractions that are semi-regular, feel real, and then stop. Prodromal labor is exhausting and demoralizing. It's not false labor (those contractions are doing something), but it's not active, progressive labor yet.
• Increased pressure and discharge. Increased vaginal discharge is normal. The mucus plug may come out in pieces over days. Bloody show is pink or red-tinged mucus and is a sign of cervical change.
• Emotional intensity. The waiting at this stage is genuinely difficult. Excitement, anxiety, impatience, and exhaustion compound each other. This is normal and valid.

Tips for Week 38

1. Hospital bag is done and in the car. If it's not, do it today. Focus on: your ID, birth plan, comfortable clothes for labor (you'll likely labor in a hospital gown, but having your own feels better), postpartum supplies, phone charger, snacks, one going-home outfit for the baby, the car seat.

2. Know the 5-1-1 rule. Contractions 5 minutes apart, lasting 1 minute each, for 1 hour — that's the general signal to head to the hospital for a first-time mother. Your provider may have different guidance based on your specific situation; confirm at your next appointment.

3. Rest without guilt. You are not failing by lying on the couch. You are conserving energy for labor, which is exactly what you should be doing. The housework can wait.

4. Eat protein-rich foods. Labor is intense physical work. Your body benefits from having adequate fuel in the days leading up to it. Don't skip meals, and prioritize foods that sustain energy.

5. Review your birth plan one more time. Share it with everyone who will be in the room. Make sure your birth partner knows your preferences as well as you do — they may need to advocate for you when you're mid-contraction.

6. Don't let casual comments derail you. The weeks of "any day now!" from well-meaning friends and family can become genuinely wearing. You don't need to respond to or engage with predictions. Your baby will come when they're ready.

When to Call Your Doctor

• Water breaking — always call; you'll likely be told to go to the hospital
• Contractions following the 5-1-1 pattern — or sooner if your provider has given specific instructions
• Heavy vaginal bleeding — this is different from bloody show
• Decreased fetal movement — your baby should still move regularly; fewer than 10 movements in 2 hours warrants a call, even at 38 weeks
• Signs of preeclampsia: severe persistent headache, visual changes, upper right abdominal pain, sudden severe swelling of face or hands
• Fever or signs of infection

Related Tools & Articles

• Due Date Calculator — Calculate your estimated due date
• Contraction Timer — track contractions in labor
• Hospital Bag Checklist — full packing list
• Pregnancy Week 39 — one week to due date
• Pregnancy Week-by-Week Overview — full timeline

Frequently Asked Questions

What is prodromal labor and how is it different from active labor? Prodromal labor (sometimes called "practice labor") consists of contractions that are semi-regular and can feel intense, but don't follow the progressive pattern of active labor. They may last for hours and then stop. Unlike Braxton Hicks, prodromal contractions are doing some work — they contribute to cervical preparation — but they're not active, progressive labor yet. It's exhausting and common in the days before delivery.

I'm 3 cm dilated at 38 weeks — how much longer until labor? Cervical dilation is not a reliable predictor of when labor will start. Some women walk around at 3–4 cm for days or even a week or more. Others go from minimal dilation to delivery quickly. Your cervix is preparing, which is a positive sign, but dilation alone cannot tell you when labor will begin.

Is it safe to eat in early labor at 38 weeks? Most providers recommend light, easily digestible foods in early labor (toast, yogurt, fruit) if you can tolerate it. Labor is physically demanding and having some energy reserves matters. Avoid heavy or fatty meals. Your care team will give you specific guidance when you arrive at the hospital about eating once active labor is established.

What should I actually pack in my hospital bag? For you: ID and insurance, birth plan copies, comfortable clothing for labor and recovery, maternity pads and comfortable underwear, nipple cream if breastfeeding, phone charger, snacks, a change of clothes for going home. For the baby: one newborn outfit, a hat, and the car seat (installed and ready). Don't overpack — hospitals have most necessities.

Can sex help start labor at 38 weeks? There is limited evidence that sex can help ripen the cervix — semen contains prostaglandins and orgasm can trigger mild uterine contractions. It won't harm the baby and may contribute to cervical preparation, but it's not a reliable method of induction. If your membranes are intact and your provider hasn't restricted sex, it's safe to try if you're comfortable.

Sources

• ACOG — Approaches to Limit Intervention During Labor and Birth
• ACOG — Definition of Term Pregnancy
• Mayo Clinic — Labor and Delivery, Postpartum Care
• March of Dimes — Signs of Labor

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