39 weeks pregnant: development, the show and warning signs
39 weeks pregnant is a stage at which, the NHS says, the baby is around 50.7 cm long from head to heel, about the size of a small watermelon (NHS, 2026), and at which the Office on Women’s Health says the baby is considered full term (Office on Women’s Health, Stages of pregnancy, 2025). This page sets out what the NHS and the Office on Women’s Health say about week 39, including the signs the NHS says you should not ignore.
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Medically reviewed by Dr Mary Davidson, Reproductive endocrinologist, checked on
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 39 weeks
- Size and shape, NHS
- The NHS week 39 page in its week-by-week guide (NHS, 2026) gives the baby as around 50.7 cm long from head to heel and compares it to a small watermelon. It says the skin is growing a tougher new layer that looks more solid, and is coated in a white, waxy substance called vernix that helps to protect the skin and eases the baby down the birth canal.
- Full term, Office on Women’s Health
- The Office on Women’s Health (2025) says that at 39 weeks the baby is considered full term and the organs are ready to function on their own. It says most babies present head down, and that at birth a baby may weigh between 6 pounds 2 ounces and 9 pounds 2 ounces and be 19 to 21 inches long.
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 39 weeks 0 days to 39 weeks 6 days.
A normal pregnancy lasts about 40 weeks from the first day of the last menstrual period, so at 39 weeks about 1 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.
Around the due date
The NHS says pregnancy normally lasts around 40 weeks and most women will go into labour a week either side of their due date (NHS, 2026). ACOG says only about 1 in 20 women give birth on their due dates (ACOG, How Your Fetus Grows During Pregnancy, 2024).
Your body at 39 weeks, as the NHS describes it
The NHS says you might get a lot more discharge than usual, which it says should be thin, white and not smell of very much. It says a slimy blob of mucus that is yellow or bloody is called a “show”, that it can be one of the first signs that the baby is on the way, and that you could still have days to wait. It also says you may have back pain as the baby moves down your pelvis and starts pressing against your spine (NHS, 2026).
Signs the NHS says you should not ignore
The NHS says that if you get any of the following you should treat it as an emergency and call your midwife, doctor or NHS 111 (NHS, 2026):
- bleeding from your vagina
- brown or pink discharge
- severe itching, particularly at night
- a terrible headache that will not go away
- vision problems, such as blurring, light sensitivity, seeing spots or flashing lights
- pain just below the ribs
- extreme swelling of the feet, ankles, hands and face
- persistent stomach pains
- a high temperature, above 37.5 degrees Celsius, with no other flu or cold symptoms
The NHS gives the UK routes for these. Wherever you are, the box above lists the symptoms that need urgent help and the numbers for the nation you choose.
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 39 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
What is the show in pregnancy?
The NHS says a slimy blob of mucus that is yellow or bloody is called a show, that it used to plug the cervix, that it can be one of the first signs that the baby is on the way, and that you could still have days to wait (NHS, 2026).
Is 39 weeks pregnant full term?
The Office on Women’s Health says a baby is considered full term at 39 weeks (Office on Women’s Health, 2025). The NHS calls the baby full term from week 37 on its week 37 page (NHS, 2026).