40 weeks pregnant: your due date week

Your due date is an estimate, not a deadline. Here is what the numbers say, how to tell when it is really starting, and what happens next if it is not.

Updated October 13, 2026 · sources checked October 13, 2026

In short

At 40 weeks you have reached your estimated due date, and your baby is about 51.2 cm from head to heel (NHS). Only about 1 in 20 babies arrive on the day itself (ACOG). The one thing to do this week: learn the difference between practice and real contractions, and call when they last 60 seconds and come every 5 minutes.

Where you are at 40 weeks

You have reached 40 weeks, the estimated due date. ACOG reminds us that it is a guide used to time tests and track growth, and that only about 1 in 20 people give birth on that day. ACOG also notes that once a due date has been set, it does not change with later scans. Cleveland Clinic counts 39 weeks 0 days to 40 weeks 6 days as full term, so you are still right on time.

What the figures say: in NHS data published by NICE, 50.3% of labours that started naturally had begun by the end of week 39, and 82.8% by the end of week 40. If you are reading this at 40 weeks, you are in very good company.

Your baby this week

The NHS gives about 51.2 cm from head to heel, comparing your baby to a pumpkin. Cleveland Clinic gives an average of 18 to 20 inches and 7 to 9 pounds at the end of month 10. There is very little room, but the NHS is clear: movements should not slow down or stop. A change in pattern is a reason to call, 24 hours a day.

Your body and common symptoms

Practice versus real contractions. Braxton Hicks tighten without real pain. Labour contractions hurt as the bump tightens, ease as it relaxes, and build in length and frequency.
Premenstrual-type feelings or lower backache can be early signs of labour, says the NHS.
Impatience. Very common, and very human.

Is this normal? When to call

Call your hospital or midwife when contractions last at least 60 seconds and come every 5 minutes, or straight away if your waters break, you bleed, your baby moves less than usual or stops moving, or you have a severe headache, vision problems, pain below the ribs, sudden swelling or a fever. UK: maternity unit (staffed day and night), NHS 111 if you cannot reach them, 999 in an emergency. US: labour and delivery or your OB-GYN, 911 in an emergency.

Eight labour tips from the NHS

If contractions start at night, try to sleep through as much as you can: your cervix can keep opening while you rest.
If they start in the day, stay upright and moving; it helps your baby move down. Our page on labor positions has ideas.
Try different positions: rock on a birth ball, or lean on your birth partner.
Have a warm bath or shower.
Breathe in through your nose and out through your mouth, jaw relaxed.
Ask for a massage and involve your birth partner.
Eat something light to keep your energy up, like a banana or a yoghurt.
Do whatever helps you feel calm.

The first stage of labour, when the cervix opens to about 10 cm, often lasts 6 to 12 hours, or less if you have given birth before (NHS).

Appointments and tests around 40 weeks

UK: if this is your first baby, you will have a 40-week appointment: blood pressure, urine, bump measurement, movements, mental health, and your choices if you are still pregnant after 40 weeks (NHS). A membrane sweep may be offered.
US: ACOG says a pregnancy between 40 and 41 weeks does not necessarily need extra testing, but your OB-GYN may plan testing from 41 weeks. Ask now what the plan would be.

Your checklist for week 40

Ask at your 40-week check: when would induction be offered, and what monitoring is available if you prefer to wait?
Keep moving, eating and resting as normally as you can.
Re-read the signs of labour with your birth partner.
Prepare a "we are not there yet" message for family, so you do not have to answer every text.
Put pads, comfortable underwear and a water bottle with a straw in your bag for after the birth.

For your partner

Guard her rest. Take the phone calls, cook, run the bath, and stay within easy reach.

Previous and next week

Week 39: full term and warning signs · Week 41: going past your due date · The third trimester · All weeks · Pregnancy week calculator · Due date calculator

Questions parents ask

How do I know if contractions are real?

The NHS explains that Braxton Hicks tighten the bump but should not be painful. Real contractions hurt as the bump tightens, then the pain fades as the muscles relax, and they become longer, stronger and closer together. Call your hospital or midwife when they last at least 60 seconds and come every 5 minutes.

How likely is labour to start this week?

NICE published NHS data from 2019-20 on labours that started on their own. About a third (32.5%) started between 40+0 and 40+6 weeks, and 82.8% had started by the end of week 40.

Can I bring on labour naturally?

The NHS says there are no proven ways to safely bring on labour at home. Ask your midwife or doctor before trying anything other than watching and waiting.

Sources

NHS — Week-by-week guide to pregnancy, week 40 checked October 13, 2026
Cleveland Clinic — Fetal development, week-by-week stages of pregnancy checked October 13, 2026
ACOG — How Your Fetus Grows During Pregnancy (due date) checked October 13, 2026
ACOG — When Pregnancy Goes Past Your Due Date checked October 13, 2026
NICE NG207 — Inducing labour, recommendations (table 1, when spontaneous labour starts) checked October 13, 2026
NHS — Antenatal (pregnancy) care and appointments checked October 13, 2026

Mamavela explains; it does not replace your midwife, doctor or pediatrician, who know your situation. If something worries you, call them. In an emergency, call 911 (US), 999 (UK) or 112.