Third trimester · Week 31 of 40

Pregnancy week 31

Brain connections multiply; hiccups are common.

Approx. length41.1 cm
Approx. weight1502 g
Size feelcabbage
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Baby development at week 31

All five senses function in early ways. Processing of sound and light continues. Hiccups can become a familiar daily pattern.

Average size estimates for week 31 are about 41.1 cm and 1502 g — roughly cabbage. Your ultrasound report and clinician’s dating override any website average.

What you might feel

Pelvic pressure and Braxton Hicks may pick up. Practice your “call the clinic if…” checklist with your provider.

You are in the third trimester. Two pregnancies at the same week can feel completely different — treat these notes as orientation, not a checklist you must match.

Movements in week 31

By now, many clinicians encourage intentional awareness of fetal movement. Learn your baby’s usual active window, then use Preglo’s kick counter to log a calm session. Read how to count baby kicks if you want a simple method, or the 10-kick count overview. If movements feel clearly reduced, contact your care provider — see reduced fetal movement.

What to track this week

A calm next step in Preglo

Use contraction timer later only when tightenings become patterned — for now, notes are enough.

Also useful: due date calculator · all weeks · Preglo features

Nearby weeks: Week 29 · Week 30 · Week 32 · Week 33

Educational averages only — not medical advice. Contact your clinician for symptoms that worry you, bleeding, severe pain, or reduced movements.

Week 31 FAQ

How big is the baby at week 31?

Typical educational averages are about 41.1 cm long and 1502 g. Individual growth and measurement methods vary.

Which trimester is week 31?

Week 31 is generally counted in the third trimester (weeks 1–12 first, 13–27 second, 28–40 third in common educational grouping).

Should I track anything special this week?

Use contraction timer later only when tightenings become patterned — for now, notes are enough.

Preglo

Track this week in Preglo.

Week tracker, kick counter, water log, and widgets — private on iPhone.

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