Pregnancy Week 38: Early Term, True Labor, and Knowing When to Go

Early term — not quite the finish line, but very close. Week 38 means your baby is almost ready. So are you. This is the week to learn the difference between a practice run and the real thing.

At 38 weeks, you are what ACOG calls "early term" — the window from 37 weeks 0 days through 38 weeks 6 days [2]. Full term doesn't begin until 39 weeks. That distinction matters: babies born in the early-term window are generally healthy, but those who wait until 39 or 40 weeks complete a final burst of brain, lung, and liver development. Unless there is a medical reason, most providers will encourage waiting.

Still — 38 weeks is very close to the end, and your body is actively preparing. This article draws on guidance from NHS [1], ACOG [2][3], CDC [4], and WHO [5].

Your baby at week 38

Your baby is about 49–50 centimeters (around 19–20 inches) long and weighs roughly 3.1 kilograms (6.8 lbs) — though there is significant normal variation.

What is happening now:

• Lungs — almost fully mature; surfactant production is nearly complete, helping the air sacs stay open after birth
• Brain and nervous system — still developing; this development continues through the early-term window and beyond (one more reason not to rush)
• Liver — maturing; builds glycogen stores that regulate blood sugar in the first hours after birth
• Lanugo — most of the fine body hair has shed; some remains on shoulders or ears, which is normal
• Vernix — the waxy white coating protecting the skin is thinning; some will remain at birth
• Fingernails — may already be long enough to scratch, especially if your baby arrives after 39 weeks
• Position — in most pregnancies, the baby is head-down (vertex) by this week; if breech, talk to your provider about options including External Cephalic Version (ECV)

Signs of labor: true versus Braxton Hicks

This is the question every parent at 38 weeks asks. According to NHS [1], there are three major signs that labor is actually starting:

1. A "show"

The mucus plug — which sealed your cervix throughout pregnancy — comes away. It looks like sticky, jelly-like pink or slightly blood-streaked mucus. This can happen as one piece or in several small pieces over a day or two. A show signals that the cervix is beginning to soften and open, but active labor may still be hours or days away.

A small amount of blood in the show is normal. Bleeding that looks like a menstrual period requires immediate medical attention.

2. Your waters breaking

The amniotic sac ruptures and fluid drains out. This may feel like a slow trickle or a sudden gush you cannot control. The fluid is typically clear and pale — sometimes slightly pink or blood-tinged at first.

Watch the colour and smell: green, brown, or dark-yellow fluid can mean meconium-stained amniotic fluid (the baby has passed stool), and a foul or unusual smell can signal infection. Either should prompt going to hospital straight away rather than calling first [1].

If your waters break, note the time, color, and smell, and call your provider or go to the hospital. The main concern is infection risk once the sac is open.

3. Regular contractions — the 5-1-1 rule

True labor contractions become longer, stronger, and closer together over time, typically lasting 60–90 seconds in a regular pattern, and they do not go away when you walk, rest, or change position [3]. Many labor-and-delivery units use the 5-1-1 rule as a practical guide for when to head in:

Contractions every 5 minutes, lasting 1 minute each, for at least 1 hour.

Braxton Hicks contractions (practice contractions, "false labor") are irregular, usually mild or painless, and typically stop when you rest, hydrate, or change position. If you time them and they are not becoming more frequent and stronger over an hour, you are likely still in the waiting phase.

Cervical effacement and dilation

Before or during early labor, the cervix effaces (shortens and thins) and dilates (opens). Your provider may check your cervix at a routine appointment, but the degree of effacement or dilation at 38 weeks does not reliably predict when labor will start — some women walk around 3 cm dilated for a week; others go from nothing to active labor quickly.

Your GBS results

If you had your Group B Streptococcus (GBS) swab between 36 0/7 and 37 6/7 weeks (the current ACOG/CDC screening window, sometimes still described as 35–37 weeks), the results should be back by now. According to CDC [4]:

• GBS negative — no special precautions needed during labor
• GBS positive — you will receive IV antibiotics during active labor to prevent transmission to your baby. The antibiotic must be given at least 4 hours before delivery to be most effective, so tell your labor team your GBS status as soon as you arrive
• Unknown status (test not done, or waters broke early) — your provider will follow a risk-based protocol

A positive GBS result does not change your birth plan or mean a caesarean is needed. It simply means the team will add one IV line and one medication during labor.

What your body is doing at 38 weeks

• Pelvic pressure — your baby may have "engaged" (dropped lower in the pelvis), making breathing easier but pelvic pressure more noticeable
• Braxton Hicks contractions — more frequent; some are uncomfortable
• Cervical changes — your provider may mention "ripening," effacement percentage, or centimeters of dilation at check-ups
• Mucus discharge — increased clear or white discharge is normal; pink-tinged mucus is the show; bright red bleeding needs immediate attention
• Fatigue, nesting instinct, low back pain — all common in the final weeks

When to go to the hospital immediately

Call your provider or go to the hospital right away if you have any of the following:

• Waters break (clear or colored fluid leaking from the vagina)
• Contractions following the 5-1-1 rule — or sooner if pain is severe
• Vaginal bleeding heavier than a show
• Baby's movements significantly reduced — if your baby is moving noticeably less than usual, call today; do not wait
• Severe headache, blurred vision, sudden swelling of face or hands — signs of pre-eclampsia
• Fever above 38°C (100.4°F) with or without other symptoms

When in doubt, call. Labor and delivery teams are used to these calls at 2 a.m. There is no such thing as a question too small at this stage of pregnancy.

Summary

Week 38 is the early-term window — baby is almost ready, and so are you.

Key points for this week:

1. You are early term, not full term. Waiting until 39 weeks gives your baby's brain and lungs the final development they need, unless your provider advises otherwise
2. Know the three signs of labor — a show, waters breaking, and regular contractions following the 5-1-1 rule
3. Braxton Hicks stop with rest — true labor contractions do not
4. Check your GBS result — if positive, tell your labor team immediately on arrival so IV antibiotics can start in time
5. Call or go in without hesitation if you see reduced fetal movement, heavy bleeding, your waters break, or you have pre-eclampsia warning signs

You have done so much work to get here. The last stretch is a waiting game, but knowing what to watch for means you won't miss the real thing.