40 weeks pregnant
Third trimester about 9 months
At 40 weeks pregnant, your baby is about the size of a watermelon.
Baby this week
About 51cm. The baby is fully developed and ready for life outside the womb. Due date has arrived — though only 5% of babies are born exactly on their due date.
Did you know? Only about 5% of babies are born on their actual due date — most arrive within two weeks on either side. The due date is a midpoint of a normal birth range, not a deadline.
What she may be feeling
- Due date symptoms vary widely
- May have strong Braxton Hicks or real contractions
- Mucus plug loss
- Pelvic pressure
- Nesting or exhaustion
- Emotional intensity
- Cervical changes
Tips for her this week
- Due date is here — but most babies arrive within a week before or after this date.
- Your provider will monitor you closely and discuss induction if you go past 41–42 weeks.
- Try to rest, eat well, and avoid obsessing over every twinge.
- You've done 40 weeks of extraordinary work. The finish line is right here.
For partners
- Due date is here. Only 5% of babies are born on the actual due date — stay patient and calm.
- If labor hasn't started, your provider will likely discuss monitoring and induction options.
- Your entire job right now is to be calm, present, and supportive. You've got this.
- Tell her you love her. Tell her she's incredible. Tell her you're ready.
Partner to-do list
- Be fully present and available — no work distractions today if possible
- Be her calm in what may feel like a storm of anticipation
- Have a beautiful, honest conversation about becoming parents
- Trust that you are both more ready than you know
This week together
- Call your provider if labor hasn't started for guidance on next steps
- Rest and spend meaningful time together
- Have a last-meal-before-baby dinner if she's up for it
- Tell each other what you love most about each other
When to call your doctor or midwife
Contact your care provider right away, or call emergency services, if she has:
- Decreased fetal movement — call immediately
- Regular contractions — call your provider
- Water breaking — call or go in
- Heavy bleeding — go immediately
- Any sudden severe symptoms
Trusted guidance: NHS: Pregnancy · NHS: Pregnancy complications · ACOG: Pregnancy · Pregnancy Info: Your pregnancy
Common questions
How big is the baby at 40 weeks?
At 40 weeks pregnant, your baby is about the size of a watermelon. About 51cm.
How many months is 40 weeks pregnant?
40 weeks pregnant is about 9 months, in the third trimester.
What can partners do at 40 weeks?
Due date is here. Only 5% of babies are born on the actual due date — stay patient and calm. If labor hasn't started, your provider will likely discuss monitoring and induction options.