Pregnancy week by week · trimester 3
🍉 40 weeks pregnant: your baby is about the size of a watermelon
At 40 weeks pregnant, you have reached your due date. Your baby is about the size of a watermelon, full term and ready to meet you whenever the time is right.
Your baby this week
Your baby is around 51.2cm long and about 3.4kg, roughly the size of a watermelon. They are full term and ready to meet you whenever the time is right. Their lungs are prepared, their suck is strong, and their senses are ready to take in your face, your voice and your smell. Your baby will recognise the sounds they have heard for months, especially you. Movements should continue in their normal pattern right up to and during labour.
You this week
Reaching your due date can feel like a big moment, or a bit of an anticlimax. Only a small number of babies arrive on the day itself, and many come a little before or after. You may feel heavy, tired, impatient, or surprisingly peaceful. Practice contractions, pressure and a show are all common. Try to fill the waiting with gentle things: a short walk, a favourite film, a nap. You are so nearly there.
Kind things to do this week
- Rest, stay hydrated, and trust your instincts.
- Keep your hospital bag and maternity notes close by.
- Plan a few small, gentle things for each day so the waiting feels softer.
Appointments around now
If this is your first pregnancy, you will usually have an appointment at 40 weeks. Your midwife may offer a membrane sweep and will talk about what happens if labour does not start on its own.
Questions to ask your midwife
- Could I have a membrane sweep, and what does it involve?
- What are my options if labour does not start by 41 weeks?
When to call your midwife or maternity unit
If your baby's movements slow down, stop or feel different to their usual pattern, contact your maternity unit straight away, day or night. Do not wait until the next day. Please also call your midwife or maternity unit if you have bleeding, fluid leaking, a severe headache, changes to your vision, sudden swelling, or itching (especially on the palms of your hands or soles of your feet). If your waters break, or you think labour has started, call your maternity unit for advice.
OBubba from bump to baby
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Questions
What if I go past my due date?
That is very common. Most babies arrive by 42 weeks. Your midwife will talk with you about a membrane sweep and, from 41 weeks, induction of labour.
How many babies are born on their due date?
Only a small number. A due date is an estimate, and it is normal for babies to arrive in the weeks either side.
Not sure how far along you are? Use the due date calculator.
Sources
OBubba gives general information. It is not medical advice and does not diagnose anything. Your midwife and maternity unit are always the right people to ask, any time of day or night.