Baby development at week 40
“40 weeks” is a statistical midpoint, not a deadline stamped on baby. Many healthy pregnancies continue to 41 weeks with monitoring. Your clinician guides timing decisions.
Average size estimates for week 40 are about 51.2 cm and 3462 g — roughly small watermelon. Your ultrasound report and clinician’s dating override any website average.
What you might feel
Daily life can feel suspended. Walk, rest, hydrate, and keep movement awareness without obsessive checking.
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 40
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
- Symptoms, mood, sleep, and energy in your daily log
- Water intake toward a simple daily goal
- Appointment dates and questions for your care provider
- Scan dates and follow-up notes after ultrasound visits
- Kick sessions once movements feel regular — same time of day when you can
- Tightenings or early labor patterns with the contraction timer if needed
- Hospital bag checklist and “call the clinic if…” reminders
A calm next step in Preglo
If you go past dates, keep logging kicks and contractions as advised — and rely on your care team for next steps.
Also useful: due date calculator · all weeks · Preglo features
Nearby weeks: Week 38 · Week 39
Educational averages only — not medical advice. Contact your clinician for symptoms that worry you, bleeding, severe pain, or reduced movements.