23 weeks pregnant: breathing practice and rib pain
23 weeks pregnant is a stage at which, the NHS says, the baby is around 28.9 cm long from head to heel, about the size of a large mango, with limbs now in proportion (NHS, 2026). This page sets out what the NHS and ACOG say about week 23.
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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 23 weeks
- Size and shape, NHS
- The NHS week 23 page in its week-by-week guide (NHS, 2026) gives the baby as around 28.9 cm long from head to heel and compares it to a large mango. It says the limbs are now in proportion and that over the next few weeks you will be kicked around by the baby and may see your tummy move.
- Breathing and sleep, NHS
- The NHS says the baby is practising breathing and getting into patterns of sleeping and waking (NHS, 2026).
- Development, ACOG
- ACOG’s list for weeks 21 to 24 includes fat forming under the skin, ridges forming 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). It does not date these to a single week.
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 23 weeks 0 days to 23 weeks 6 days.
A normal pregnancy lasts about 40 weeks from the first day of the last menstrual period, so at 23 weeks about 17 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.
Your body at 23 weeks, as the NHS describes it
The NHS says your breasts may start leaking colostrum, an early type of milk. It says you may start to get rib pain as your rib cage expands to make room for your bump, and that you may feel more breathless than usual as the growing baby puts pressure on your lungs. It gives putting your feet up and relaxing as the best remedy for that, and asks you to talk to your midwife or doctor if you are worried about any symptom of pregnancy (NHS, 2026).
Whooping cough vaccination
The NHS says the whooping cough vaccine is usually offered around week 20 and can be had from week 16 to week 32 (NHS, 2026).
Baby movements after 24 weeks
NICE guideline NG201 says that from 24 weeks care teams should discuss the baby’s movements at each antenatal contact, and that a pregnant woman should contact maternity services at any time of day or night if she has any concern about the baby’s movements or notices reduced movements (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 23 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.
- National Institute for Health and Care Excellence. Antenatal care (NG201). NICE, 2021.
Frequently asked questions
How big is the baby at 23 weeks pregnant?
The NHS says around 28.9 cm long from head to heel, about the size of a large mango (NHS, 2026).
What does the NHS say about breathlessness at 23 weeks?
The NHS says you may feel more breathless than usual as the growing baby puts pressure on your lungs, and asks you to talk to your midwife or doctor if you are worried about any symptom (NHS, 2026). This page cannot say whether breathlessness is expected in your case. The box above lists symptoms that need urgent help.