37 weeks pregnant: when full term begins and signs of labour
37 weeks pregnant is a stage at which, the NHS says, the baby is around 48.6 cm long from head to heel, about the length of a leek, and is what the NHS calls full term (NHS, 2026). This page sets out what the NHS, ACOG and the Office on Women’s Health say about week 37, including where they place full term.
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Seek help now if you have any of these symptoms
Bleeding and cramping are common in early pregnancy and often do not mean miscarriage. The symptoms below, however, need to be assessed straight away.
- Soaking two or more sanitary pads per hour, or passing large clots
- Severe lower abdominal pain, especially on one side
- Pain at the tip of the shoulder
- Dizziness, fainting, or collapse
- Signs of shock — pale, clammy, rapid heartbeat, breathlessness
- Pain on opening bowels, or bladder or bowel changes
- Feeling very unwell, or feverish
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How the sources describe development around 37 weeks
- Size and shape, NHS
- The NHS week 37 page in its week-by-week guide (NHS, 2026) gives the baby as around 48.6 cm long from head to heel and compares it to the length of a leek. It says the baby will be trying out different facial expressions, such as frowning and smiling, which it says is random and not linked to sadness or happiness.
- Development, ACOG
- ACOG groups weeks 37 to 40 together. Its list includes the circulatory and musculoskeletal systems being done developing, the lungs, brain and nervous system finishing their development, and fat continuing to be added all over to keep the baby warm after birth (ACOG, How Your Fetus Grows During Pregnancy, 2024). The list is not broken down week by week.
- Size at birth, Office on Women’s Health
- The Office on Women’s Health page on the stages of pregnancy (2025) says that at birth a baby may weigh somewhere between 6 pounds 2 ounces and 9 pounds 2 ounces and be 19 to 21 inches long, that most full-term babies fall within these ranges, and that healthy babies come in many sizes.
Weeks are counted from the first day of the last menstrual period, so about two weeks of the count come before conception (ACOG, How Your Fetus Grows During Pregnancy, 2024). This page covers 37 weeks 0 days to 37 weeks 6 days.
A normal pregnancy lasts about 40 weeks from the first day of the last menstrual period, so at 37 weeks about 3 weeks remain to the estimated due date (ACOG, How Your Fetus Grows During Pregnancy, 2024). Your own due date depends on your last period or a scan, not on the week alone.
When full term starts: the sources differ
The NHS week 37 page says the baby is now full term, which it says means the baby is probably big enough and mature enough to survive in the outside world, and that you could still have to wait another few weeks (NHS, 2026). The Office on Women’s Health says that at 39 weeks the baby is considered full term (Office on Women’s Health, 2025). Two documents, two starting weeks, and this page cannot say which is right for you. Your care team can explain the terms they use.
Your body at 37 weeks, as the NHS describes it
The NHS says around 95% of babies are now head down, facing their mother’s back, and that when the head moves down into the pelvis it is said to be engaged and you might see your bump drop a bit. It says you might get more vaginal discharge and Braxton Hicks contractions, which can feel uncomfortable but should not be painful, and a sudden urge to spring clean, which it calls the nesting instinct (NHS, 2026).
Signs that labour may be starting, as the NHS lists them
The NHS lists contractions or tightenings, a “show”, when you get a sticky blob of mucus in your pants that might be yellow or bloody, back pain, an urge to go to the toilet, and your waters breaking. It says its guide on the signs of going into labour includes when to call your midwife or maternity unit (NHS, 2026). How practice contractions differ from labor is covered in the guide to Braxton Hicks. The box above lists the symptoms that need urgent help.
Work out which week you are in
The Pregnancy week calculator takes your last period, conception date, scan or IVF transfer and shows how many weeks and days pregnant you are today.
Sources
- NHS Best Start in Life. Week 37 of pregnancy (week-by-week guide to pregnancy). nhs.uk, 2026.
- American College of Obstetricians and Gynecologists. How Your Fetus Grows During Pregnancy (FAQ156). ACOG, 2024.
- Office on Women's Health, US Department of Health and Human Services. Stages of pregnancy. womenshealth.gov, 2025.
Frequently asked questions
Is 37 weeks pregnant full term?
The NHS says yes: on its week 37 page the baby is full term (NHS, 2026). The Office on Women’s Health says a baby is considered full term at 39 weeks (Office on Women’s Health, 2025). The two bodies use different starting weeks.
What are the signs of labour at 37 weeks?
The NHS lists contractions or tightenings, a show, back pain, an urge to go to the toilet and your waters breaking (NHS, 2026). Contact your midwife or maternity unit if you are unsure. The box above lists symptoms that need urgent help.