Baby is the size of a big watermelon
👶 Baby's development
Fully ready to meet the world! Average newborn: 50–51 cm, 3.2–3.5 kg.
💛 How mom feels
Due date has arrived. If no contractions, the doctor will schedule induction. You've got this 💪
📖 Tip of the week
The baby is fully ready! If labor hasn't started, your doctor will discuss induction. Don't worry — most "overdue" babies are born perfectly healthy. You're about to meet each other — you've done an amazing job! 💕
🔬 Detailed baby development
- The baby is at its full-term due date — ready to be born and meet you
- The baby's skull bones are not yet fused, allowing them to overlap during passage through the birth canal (molding)
- The lungs are mature with adequate surfactant for independent breathing
- The baby has about 300 bones (adults have 206 — many fuse together as the child grows)
- The baby's immune system is functional but will continue to strengthen with breast milk antibodies
- The average baby at 40 weeks is about 51 cm long and weighs approximately 3,400 grams (7.5 lbs)
🤱 What mom may feel
- You may experience 'lightning crotch' — sharp, shooting pains in the pelvis as nerves are compressed
- Cervical changes continue: increased dilation and effacement
- Possible rupture of membranes (water breaking) either as a gush or a slow trickle
- True labor contractions may begin: regular, progressively stronger and closer together
- Nesting instincts peak — last-minute urges to prepare
- Mix of excitement, nervousness, and impatience
🏥 Tests and check-ups
Weekly prenatal visit continues. If labor has not begun, your provider will discuss induction options. Non-stress tests and amniotic fluid checks may be performed to ensure the baby is doing well. Most providers recommend induction between 41-42 weeks to reduce the risk of complications from post-term pregnancy.
💡 Tips for this week
- Stay calm and trust your body — you have prepared for this
- Time your contractions using a contraction timer app: note the start time, duration, and interval between them
- Go to the hospital when contractions are consistently 5 minutes apart, lasting 1 minute each, for at least 1 hour (the 5-1-1 rule)
- If your water breaks, note the time, color (should be clear), and amount, then contact your provider
- Remember that your due date is an estimate — healthy babies arrive on their own schedule
❓ Frequently asked questions
What happens if labor doesn't start by 40 weeks?
About half of all pregnancies extend past 40 weeks. Your provider will increase monitoring and typically recommend induction between 41-42 weeks. Research shows induction at 41 weeks reduces the risk of stillbirth and cesarean delivery without increasing complications.
What does it feel like when water breaks?
It can feel like a sudden gush of warm fluid or a slow, continuous trickle that you cannot control. The fluid should be clear and odorless or slightly sweet-smelling. If it is green, brown, or foul-smelling, go to the hospital immediately as it may indicate meconium.
How long does labor typically last?
For first-time mothers, labor averages 12-18 hours from active labor to delivery. Subsequent births are often faster, averaging 8-10 hours. However, every labor is unique. Early labor (before active dilation) can last many additional hours.
What if I need a cesarean section?
Cesarean deliveries are performed when vaginal delivery poses risks to mother or baby. Common reasons include failure to progress, fetal distress, breech presentation, or placenta problems. About 30% of births in the US are cesarean. Recovery typically takes 6-8 weeks.
📝 Week 40 of pregnancy: preparing for birth
You have reached your due date — 40 weeks of pregnancy. Your baby now weighs on average 3.4 to 3.5 kg and measures approximately 51 cm — though there is a wide normal range and every baby is different. In reality, only around 5% of babies are born on their estimated due date, with most arriving within two weeks either side. Every organ system is fully prepared for independent life, and your baby is simply waiting for the right moment. If your baby has not yet arrived, try to remain patient — your body and your baby will work together when the time is right.
At 40 weeks, you are likely feeling a combination of impatience, excitement, and physical exhaustion. The weight of the baby, increased pelvic pressure, disrupted sleep, and the anticipation of labour can all make this a challenging time emotionally. Remember that your due date is an estimate, not a deadline, and going a few days or even up to two weeks over is very common. Continue monitoring your baby’s movements closely — you should still feel regular movements right up until labour and during labour itself. A change in movement pattern should always be reported to your midwife.
At your 40-week appointment, your midwife will offer a membrane sweep if not already performed, and will discuss plans for induction of labour should the pregnancy continue beyond 41 weeks. In the UK, induction is typically recommended by 41 to 42 weeks in line with NICE guidelines, as the risk of stillbirth increases slightly beyond this point. Your midwife will explain what induction involves — which may include prostaglandin gel or pessary, artificial rupture of membranes, and/or an oxytocin drip — so that you can make an informed decision. A post-dates CTG (cardiotocography) may also be offered to assess the baby’s heart rate and wellbeing.
While you wait for labour to begin, focus on comfort and conservation of energy. Gentle walks, time in a warm bath, and time spent on a birthing ball can help encourage the baby’s head to press on the cervix and stimulate contractions. Contact your maternity unit if you experience any of the following: regular contractions (3 to 5 minutes apart, lasting 60 seconds), waters breaking, heavy bleeding, reduced or absent movements, or severe headache or visual disturbances. You are almost there — labour and birth are imminent, and very soon you will be holding your newborn. Trust yourself, trust your body, and know that the midwives and doctors supporting you are with you every step of the way.
⚠️ When to see a doctor
- Vaginal bleeding
- Sudden decrease in baby movements (fewer than 10 in 2 hours)
- Severe headache or seeing spots
- Swelling of face, hands, or sudden leg swelling
- Leaking or gushing of amniotic fluid
- Regular contractions before 37 weeks (every 10 minutes)
- Fever above 38°C (100.4°F)
Sources
- WHO recommendations on antenatal care (2016)
- ACOG Practice Bulletins
- Williams Obstetrics, 26th Edition
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