Pregnancy Week 37: Early Term — What That Label Really Means

"Early term" is not the same as "full term." Week 37 — your baby could arrive any day now, but two more weeks in the womb still matters. Know the signs of real labor, and know when to go.

At 37 weeks, many parents expect to hear "your baby is full term" — and some providers do use that phrase loosely. But the precise clinical definition, set by ACOG [2] and widely adopted since 2013, places early term at 37 0/7 through 38 6/7 weeks, and full term at 39 0/7 through 40 6/7 weeks. Those two extra weeks of organ maturation — particularly for the brain and lungs — are not trivial.

This article draws on the NHS [1], ACOG [2], Mayo Clinic [3], CDC [4], and WHO [5].

Your baby at week 37

Your baby is about 48.6 centimeters (roughly the length of a leek) and weighs approximately 2.9 kilograms (6.4 lbs), according to NHS data [1].

What's happening this week:

• Position — about 95% of babies are head-down (cephalic) by now; if yours isn't, your provider may discuss options including External Cephalic Version (ECV)
• Lungs — still maturing; the last weeks of pregnancy add critical surfactant that keeps air sacs open after birth
• Brain — significantly lighter at 37 weeks than at 39–40; the final weeks of gestation add gray matter that matters for learning and coordination later
• Grasp reflex — strong; your baby can grip a finger tightly at birth
• Fat layer — building steadily, which helps regulate body temperature outside the womb
• Practice behaviors — swallowing, sucking, blinking, and making facial expressions like frowning or smiling

Why "early term" vs "full term" matters

ACOG's official gestational-age terminology [2]:

Why it matters in practice: babies born at 37–38 weeks have higher rates of respiratory distress, feeding difficulties, temperature instability, and NICU admission compared to babies born at 39–40 weeks. Unless there is a medical reason to deliver early, waiting to 39 weeks when possible is better for the baby.

Symptoms you may notice

Lightening — baby drops lower

For many moms, especially first-time pregnancies, the baby descends into the pelvis (called "lightening" or "engagement") in the final weeks before labor. You may notice:

• Belly shape shifts lower — your bump appears to have "dropped"
• Easier breathing — less pressure against your diaphragm
• More pelvic pressure — heaviness or pressure deep in the pelvis
• More frequent urination — the baby's head now presses on your bladder more directly

Braxton Hicks contractions — still not the real thing

Irregular, practice contractions are common and often stronger at 37 weeks. They can sometimes be uncomfortable or even painful, but they differ from true labor in three ways:

• Irregular — no consistent pattern; intervals do not get progressively shorter
• Do not intensify over time — the strength does not build in a steady ramp
• Often ease with rest, hydration, or a change of position — true labor contractions do the opposite: they keep going regardless of position and tend to intensify with walking

Other common symptoms

• Increased vaginal discharge — whitish or clear discharge often increases as the cervix softens; contact your provider if it smells unusual, is yellow-green, or is accompanied by itching
• Mucus plug / bloody show — a small discharge of pink or brown-tinged mucus from the cervix; can happen days or hours before labor, or not at all
• Backache — lower back and pelvic aching from the weight and position of the baby
• Leg swelling — moderate ankle swelling is normal; sudden severe swelling in the face or hands warrants a call to your doctor
• Difficulty sleeping — common in late pregnancy; a pillow between the knees often helps

GBS screening — if you haven't had it yet

According to ACOG [2], all pregnant women should be screened for Group B Streptococcus (GBS) between 36 and 37 weeks. The Mayo Clinic confirms [3] this is the standard recommendation.

What you need to know:

• GBS is a bacterium that lives harmlessly in the vagina and rectum of about 1 in 4 healthy women — it causes no symptoms in adults
• The risk — if passed to the baby during delivery, it can cause serious newborn infections (pneumonia, meningitis, bloodstream infection)
• The test — a quick swab of the vagina and rectum; takes seconds
• If positive — IV antibiotics during labor are highly effective at protecting your baby; CDC confirms [4] intrapartum antibiotic prophylaxis significantly reduces early-onset GBS disease
• GBS-positive does not mean cesarean — it is not, by itself, an indication for surgical birth

Monitoring fetal movement

Tracking your baby's movements remains important in the final weeks, but current guidance from the NHS [1] and WHO [5] emphasizes knowing your baby's individual normal pattern rather than counting to a fixed number — every baby is different, so there is no universally recommended "minimum" count.

What this looks like in practice:

• Movements typically change in character near term (less rolling, more stretching and pushing of limbs) because there is less space — but the frequency should not drop noticeably from your baby's usual pattern [1]
• If movements feel reduced, try lying on your left side and drinking something cold, then watch for activity again
• If movements are still less than usual, do not wait until the next routine appointment — call your provider or go to the hospital the same day. Labor and delivery teams expect these calls and would much rather check than miss something

When to go to the hospital

Contact your provider or go to the hospital right away if you experience:

• Regular, painful contractions — follow the 5-1-1 rule: contractions every 5 minutes, lasting 1 minute each, for at least 1 hour
• Water breaking (rupture of membranes) — whether a dramatic gush or a slow trickle of clear fluid; note the time, color, and smell
• Bloody show followed immediately by contractions — a small amount of pink mucus on its own is often normal, but heavy bleeding is not
• Significantly reduced fetal movement — fewer movements than usual for more than a few hours
• Severe headache, blurred vision, or sudden facial/hand swelling — warning signs of pre-eclampsia requiring emergency evaluation
• Fever above 38°C (100.4°F)
• Severe abdominal pain that does not ease

When in doubt, call your care team. Labor and delivery units are accustomed to these calls at all hours — there is no question too small this late in pregnancy.

Summary

Week 37 is a milestone, but the final two weeks before 39 weeks still matter for your baby's development.

Key priorities this week:

1. Know the difference: early term (37–38 weeks) ≠ full term (39–40 weeks) — staying in the womb until 39 weeks is better if medically possible
2. Complete GBS screening if you haven't already (36–37 weeks is the window)
3. Learn the 5-1-1 rule for real labor contractions and know when to go
4. Monitor fetal movement daily — report significant reduction the same day
5. Hospital bag should be packed and car seat installed — you could go into labor any day now
6. Know your warning signs: water breaking, heavy bleeding, pre-eclampsia symptoms, reduced movement

Every pregnancy is different. If something doesn't feel right, trust your instinct and call your provider.