38 weeks pregnant

How big is your baby at 38 weeks?

About the length of a stick of rhubarb — around 49.8 cm (19.6 in) head to heel. The furry coat of soft downy hair (lanugo) that covered your baby in the second trimester is mostly gone, though some babies are born with patches here and there.

A note on the numbers: these are head-to-heel lengths. The NHS gives one for every week of the third trimester but no weekly weight — the only weight it publishes in this range is at 41 weeks, where the average baby is around 3 to 4 kg (6 lb 10 oz to 8 lb 13 oz).

What's developing this week

Your baby is storing meconium — the sticky dark green contents of the bowel, everything swallowed in the womb, including amniotic fluid and hair. It normally comes out as the first nappy after birth. The NHS adds the reason it is mentioned at all: if your baby passes meconium during labour it can be a sign of distress, and they will need close monitoring. Everything else is finishing touches.

What you might feel

The NHS names the week-38 symptom that no other guide does: frustration, or even boredom. You are ready, the bag is packed, and nothing is happening. That is not a failure of anything.

Physically: Braxton Hicks that are getting harder to dismiss, pressure low in your pelvis, backache, broken sleep, heartburn, swelling in your hands and feet, and the ordinary indignities of a body at capacity. Anything sudden or severe in that list — particularly swelling of the face, a headache that will not shift, or vision changes — is a phone call, not a symptom.

Movements do not slow down at the end

The bag being packed changes nothing here. This is still the call that comes before all the others. Call your midwife or maternity unit immediately if your baby is moving less than usual, if you cannot feel them moving, or if their usual pattern has changed — do not wait until the next day, do not wait for your next appointment, and call even in the middle of the night. Those are the NHS's own words, and maternity triage is staffed 24 hours a day for exactly this call.

Babies do not move less at the end because they have run out of room. The RCOG says movements tend to increase until about 32 weeks then stay roughly the same, and that you should feel your baby move right up to and during labour. Nor do you need to count: the NHS says "you do not need to count the number of kicks or movements you feel each day", and RCOG Green-top Guideline No. 57, second edition, reviewed 29 April 2026, found insufficient evidence to recommend counting using specified numbers. What matters is a change from your baby's own pattern.

Tommy's reports that 55% of women who had a stillbirth had noticed their baby's movements slow down or stop and had not reported it. Our movements counter records what normal looks like for your baby, but no number on it means everything is fine — and a home Doppler is worse: the NHS says hearing a heartbeat does not mean your baby is well.

Is 38 weeks pregnant 8 months or 9 months?

Week 38 is in month 9, its third week. On the American labels you are still early term until the end of this week; full term starts at 39+0.

There is no official weeks-to-months map, and a calendar month averages 4.3 weeks rather than 4, so 40 weeks is a little over nine months. The usual mapping:

• Month 1 — weeks 1 to 4
• Month 2 — weeks 5 to 8
• Month 3 — weeks 9 to 13
• Month 4 — weeks 14 to 17
• Month 5 — weeks 18 to 22
• Month 6 — weeks 23 to 27
• Month 7 — weeks 28 to 31
• Month 8 — weeks 32 to 35
• Month 9 — weeks 36 to 40

Your maternity team counts in weeks and days. Our weeks to months converter shows both mappings.

What's happening at your appointments around now

You have a 38-week appointment. Alongside the usual — blood pressure, urine, measuring your bump, feeling for your baby's position, movements, mental health — the NHS schedule adds one specific item: discuss your choices if you are still pregnant after 40 weeks.

Your midwife or doctor will check your urine for protein, which alongside high blood pressure is the early sign of pre-eclampsia. The NHS notes you are unlikely to notice those two signs yourself, which is the entire reason these appointments exist.

If you are having a planned caesarean it will usually be booked for at least 39 weeks, to give your baby's lungs the best chance of being fully developed.

The conversation about going past your due date starts now

Have it properly this week, while you are not tired and frightened and being asked to decide something in a corridor.

NICE's starting position is unambiguous: "Give women with uncomplicated pregnancies every opportunity to go into spontaneous labour." It also asks clinicians to explain that labour usually starts naturally before 42+0 weeks, and publishes the distribution to prove it. From NHS maternity data, of all labours that started spontaneously: 24.9% had started by the end of week 38, 50.3% by the end of week 39, 82.8% by the end of week 40, and 99.0% by the end of week 41.

Around 1 in 5 UK labours are induced. NICE's rules about how that is offered matter more than the number: you must be given time to discuss it with whoever you want, the chance to ask questions, and it must be recorded that you can decide to proceed with, delay, decline or stop an induction — and your decision must be respected even if the healthcare professionals disagree with it. That is written into the guideline, not a courtesy.

If your waters break before contractions start

It is usual to go into labour within 24 hours of your waters breaking. If you do not, the NHS says you will be offered an induction, because without amniotic fluid there is a small increased risk of infection for your baby.

Practicalities: use a period pad rather than a tampon, so your midwife can check the colour. Amniotic fluid is clear and pale and may be a little bloodstained at first. Tell your midwife immediately if the fluid is smelly or coloured, or if you are losing blood. While you wait, take your temperature every 4 hours when awake and report anything above about 37.5C, and ring straight away if your baby moves less than usual. There is no evidence a bath or shower increases infection risk, but having sex might.

Two country notes. ACOG lists "your water has broken and you are not having contractions" as a reason to go to hospital rather than phone. And the RCOG says that if your waters break after 37 weeks and you are known to carry group B strep, you will be offered induction straight away plus antibiotics.

When to call your midwife or doctor

These do not wait until morning.

Emergency now: 999 in the UK and Ireland, 911 in the US and Canada, 000 in Australia, 111 in New Zealand

• You think your baby is coming now and you have a strong urge to push
• You have a seizure, or you collapse

Call your midwife or maternity unit immediately, whatever the hour

• Your baby is moving less than usual, or the pattern has changed
• Your waters break — and again if the fluid is smelly, green or bloodstained
• Any vaginal bleeding
• Any contraction lasting longer than 2 minutes, or 6 or more contractions in every 10 minutes
• A severe headache painkillers do not shift, blurred vision or flashing lights, pain just below the ribs, sudden swelling of your face, hands or feet, vomiting or feeling very unwell — the NHS pre-eclampsia symptoms
• Severe itching at night, a temperature above 37.5C with no cold or flu symptoms, or persistent stomach pain
• You feel that something is wrong, without being able to say what

You do not need to be sure — units would rather see you twice than too late.