37 weeks pregnant

How big is your baby at 37 weeks?

About the length of a leek — around 48.6 cm (19.1 in) head to heel. The NHS notes your baby is now trying out facial expressions, frowning and smiling, which is random rehearsal rather than mood. Around 95% are head down by now, facing their mother's back, which is the best position for labour.

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

Nothing dramatic, which is the point: the NHS says your baby could come any day and it would not be considered early. If your baby is still breech there is time. If you are carrying twins, this is likely to be your week — the NHS notes twin pregnancies rarely go beyond 38 weeks.

What you might feel

More vaginal discharge, more Braxton Hicks — practice contractions that can be uncomfortable but should not be painful — and possibly a sudden urge to scrub the skirting boards. That is nesting, and the NHS asks you not to overdo it.

As your baby moves down into your pelvis, heartburn, indigestion and the constant need to pee may all ease off. Backache, broken sleep, swollen feet, leg cramps and piles are less inclined to.

Movements do not slow down at the end

Nothing about being at term changes this. You should feel your baby move right up to and during labour. 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 37 weeks pregnant 8 months or 9 months?

Week 37 is in month 9, its second week.

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 "term" actually means, and why 37 weeks is not "full term" everywhere

The NHS week 37 page says your baby is now "full term". American guidance disagrees with that label, and the disagreement is deliberate.

ACOG, with the Society for Maternal-Fetal Medicine, replaced the single word "term" in 2013, because outcomes are not uniform across the five weeks it covered:

• Early term — 37+0 to 38+6 weeks
• Full term — 39+0 to 40+6 weeks
• Late term — 41+0 to 41+6 weeks
• Post-term — 42+0 weeks and beyond

ACOG discourages using "term" for everything between 37+0 and 41+6, because adverse neonatal outcomes — respiratory problems in particular — are least frequent in uncomplicated pregnancies delivered between 39+0 and 40+6. At 37 weeks you are early term on the American labels, which is why elective procedures are not scheduled before 39 weeks. NICE's figures show only 12.8% of spontaneous labours have started by the end of week 37: being term does not make you imminent.

Signs of labour, and when to call — by country

The NHS lists the signs: contractions or tightenings, a "show" (a sticky blob of mucus, possibly yellow or bloody, as the plug in your cervix comes away), backache, an urge to go to the toilet from your baby's head pressing on your bowel, and your waters breaking. A show can be followed by labour quickly or by days of nothing, and sometimes there is none at all. What differs between countries is not the signs — it is the threshold for picking up the phone.

United Kingdom — NHS

Call your midwife or maternity unit if you think you are in labour, or if contractions are coming every 5 minutes or more often. There is no minimum length for each one and no hour of waiting to serve. Call 111 if you cannot reach your unit.

One inconsistency worth naming, because it causes delay: the NHS week-by-week guide phrases this as contractions that "last for at least 60 seconds and come every 5 minutes". The NHS signs-of-labour page — the one maternity units point to — asks only for every 5 minutes or more often. Five minutes apart and 40 seconds long still meets it.

United States — ACOG

You have probably met 5-1-1: contractions five minutes apart, lasting one minute, holding for one hour. It is a United States convention taught by hospitals and childbirth educators. ACOG does not publish it as a rule. What ACOG says is to time your contractions and call your ob-gyn if you think you are in labour or are not sure. Its test: true-labour contractions come at regular intervals, get closer together, last 60 to 90 seconds, and the pain starts in the back and moves to the front. False ones are felt only in the front and ease with rest or water.

Australia — Pregnancy, Birth and Baby

Australian services count contractions per ten minutes rather than minutes apart: go in with at least 3 contractions in 10 minutes for a first labour, getting stronger and taking more of your focus. Also for waters breaking, bleeding that is not a mucousy show, any change to your baby's movement pattern, fever, pain that does not come and go, contractions before 37 weeks, or if you "feel something is wrong" — which "doesn't need to be based on anything specific".

Three countries, three lines, one labour. Our contraction timer measures start to start, which is how all three thresholds are written, and reports each separately.

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.