24 weeks pregnant: testing for gestational diabetes
24 weeks pregnant is a stage at which, the NHS says, the baby is around 30 cm long from head to heel, about the size of a corn on the cob, and could survive with the right support if born now (NHS, 2026). This page sets out what the NHS, ACOG and the Office on Women’s Health say about week 24, including when testing for gestational diabetes happens.
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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 24 weeks
- Size and shape, NHS
- The NHS week 24 page in its week-by-week guide (NHS, 2026) gives the baby as around 30 cm long from head to heel and compares it to a corn on the cob. It says everything is in proportion, though the baby is smaller than one who has been in the womb for longer.
- Size and development, Office on Women’s Health
- The Office on Women’s Health page on the stages of pregnancy (2025) says that at 24 weeks bone marrow begins to make blood cells, taste buds form on the tongue, footprints and fingerprints have formed, real hair begins to grow on the head, the lungs are formed but do not work, and the baby sleeps and wakes regularly. It says the baby is at about 12 inches long and weighs about 1½ pounds. The NHS and the Office on Women’s Health each give their own size, and this page does not convert one into the other.
- Development, ACOG
- ACOG’s list for weeks 21 to 24 includes kicks and turns getting stronger, the sucking reflex developing, fat forming under the skin, ridges in the hands and feet that later become fingerprints and footprints, and skin that is wrinkled and reddish from visible blood vessels (ACOG, How Your Fetus Grows During Pregnancy, 2024).
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 24 weeks 0 days to 24 weeks 6 days.
A normal pregnancy lasts about 40 weeks from the first day of the last menstrual period, so at 24 weeks about 16 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.
Being born at 24 weeks, as the NHS describes it
The NHS says a baby at this stage is considered viable, meaning they could survive if born now and given the right support. It says that neonatal units for premature babies can help them breathe, feed, keep warm and fight infections, and it links to its page on premature labour and birth (NHS, "Week 24 of pregnancy", 2026). The box above lists symptoms that need urgent help at any stage.
Testing for gestational diabetes: the windows differ
- The NHS page on antenatal appointments says that if you have a higher chance of gestational diabetes you will be offered testing between 24 and 28 weeks (NHS, "Antenatal (pregnancy) care and appointments", 2026).
- ACOG says a glucose screening test usually takes place between 24 and 28 weeks, and may be done in the first trimester if you have risk factors for diabetes or had gestational diabetes before (ACOG, Routine Tests During Pregnancy, 2024).
- The Office on Women’s Health describes a glucose challenge screening at 26 to 28 weeks (Office on Women’s Health, Prenatal care and tests, undated).
These describe the screening arrangements of two countries and three documents. Your care team decides which tests you are offered and when. The gestational diabetes test guide sets out who is offered which test in each country and how each one works.
Your body at 24 weeks, as the NHS describes it
The NHS says you may start to feel really hungry, that you are likely to be putting on weight, and that every pregnancy is different, including how much of a bump can be seen (NHS, "Week 24 of pregnancy", 2026). NICE guideline NG201 recommends measuring the height of the top of the womb at each antenatal appointment after 24 weeks 0 days for women with a singleton pregnancy, no more often than every 2 weeks (NICE, 2021).
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 24 of pregnancy (week-by-week guide to pregnancy). nhs.uk, 2026.
- NHS. Antenatal (pregnancy) care and appointments. nhs.uk, 2026.
- National Institute for Health and Care Excellence. Antenatal care (NG201). NICE, 2021.
- American College of Obstetricians and Gynecologists. How Your Fetus Grows During Pregnancy (FAQ156). ACOG, 2024.
- American College of Obstetricians and Gynecologists. Routine Tests During Pregnancy (FAQ133). ACOG, 2024.
- Office on Women's Health, US Department of Health and Human Services. Stages of pregnancy. womenshealth.gov, 2025.
- Office on Women's Health, US Department of Health and Human Services. Prenatal care and tests. womenshealth.gov.
Frequently asked questions
How big is the baby at 24 weeks pregnant?
The NHS says around 30 cm long from head to heel, about the size of a corn on the cob (NHS, 2026). The Office on Women’s Health says about 12 inches and about 1½ pounds (Office on Women’s Health, 2025). The two bodies give different figures.
When is the glucose test?
ACOG says usually between 24 and 28 weeks (ACOG, 2024), the NHS says between 24 and 28 weeks if you have a higher chance of gestational diabetes (NHS, 2026), and the Office on Women’s Health describes a screening at 26 to 28 weeks (Office on Women’s Health, Prenatal care and tests, undated).