Baby by Week
By Muhammed Shuweck · Updated 11 August 2026
Week 31

Your week 31 guide

Rapid brain, lung and fat development continues while your baby practises increasingly coordinated movement. Space is running short, and that changes how movement feels. SubhanAllah, so much is still unfolding behind every little stretch.
Trimester

3

Month

8

Weeks left

9

Size at a glance

Comparison
Coconut
Length
46 cm
Weight
> 3 lb
Measurements are approximate. Healthy babies grow at different rates.

Baby development

The brain is forming more connections and can process information from the senses. Your baby can now register touch, sound, light and taste and respond to them in a coordinated way rather than by simple reflex. The pace of this connection-building is one of the reasons the final weeks of pregnancy carry so much value.
The lungs continue maturing but are not yet ready for independent breathing. The air sacs are still multiplying and the production of surfactant is still increasing, and both need more time. This is why babies born now usually need breathing support, and why every additional week improves the outlook.
Growth means movement feels more like rolling and stretching than large flips. Your baby is running out of room to turn completely, so somersaults become rare while pushes, presses and squirms continue. Less dramatic movement is expected; less movement overall is not, and remains something to report.

Your body

Bladder pressure, back pain, clumsiness, headaches and poor sleep can all increase. The clumsiness is real rather than imagined, caused by a shifted centre of gravity and looser ligaments, so stairs and wet floors deserve more attention than usual. Headaches are common, but a severe headache that will not lift, especially with visual changes, needs urgent assessment.
Breathlessness can occur as the uterus pushes upward against your diaphragm. Your lungs have less room to expand, so you may be out of breath after a flight of stairs you used to take easily. This eases for many women when the baby drops lower toward the end; breathlessness that is sudden or severe is a different matter and needs immediate attention.
Forgetfulness in pregnancy is widely reported and can make notes and reminders genuinely useful. Broken sleep and a heavy mental load account for much of it, and it does not indicate anything lasting. Writing things down is a more effective response than trying harder to remember.

This week's checklist

Pack or at least outline a hospital bag based on where you are giving birth. Some units provide nappies and towels and others provide nothing, so ask rather than guess. Having it roughly ready now removes one thing to think about if labour starts sooner than expected.
Learn the signs of preterm labour and know exactly who to call outside working hours. Regular tightenings, low backache, pelvic pressure, a change in discharge or any fluid loss before thirty-seven weeks all need immediate assessment. Preterm labour can sometimes be slowed to allow treatment that helps your baby's lungs, which is why calling early genuinely matters.
Finish the essential safety tasks in the nursery or sleep space before the decorative ones. A firm, flat, clear sleep surface in your room for the first six months is the part that affects safety; the paint colour is not. Avoid the ladder and the heavy lifting, and let someone else do the assembling. InshaAllah, sharing the setup work can leave you more room to rest.
Vitamin C still matters: Vitamin C supports normal tissue health and helps your body absorb iron from plant foods. A varied intake of vegetables and fruit usually provides plenty.
Sources include peppers, tomatoes, broccoli, cabbage, citrus fruits, berries, kiwi and papaya. High-dose vitamin C supplements are not a substitute for a varied diet and should not be started without professional advice.

Call your care team

Call maternity care immediately about reduced movement, bleeding, leaking fluid, or regular painful contractions, because this is still preterm.
Seek urgent help for a severe headache or vision changes, chest pain, fainting, severe abdominal pain, or breathlessness that is sudden or severe.

Medical information, not medical advice

Every pregnancy is different. Use this guide for general education and follow the advice of your own maternity care team. Do not delay urgent care because of something you read here.