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Second trimester

23 weeks pregnant

At 23 weeks your baby's limbs are now in proportion and the body is starting to store fat. You may notice stronger kicks, and some people get rib pain, breathlessness or leaking colostrum as the bump grows.

This page covers 23 weeks 0 days to 23 weeks 6 days (23+0 to 23+6), counted from the first day of the last period. Check how far along you are

Enter it to see the calendar dates of your week 23.

Botanical illustration of an acorn squash

About the size of an acorn squash

Typical estimated weight 570 g (1 lb 4 oz) at 23+0, about 655 g (1 lb 7 oz) by 23+6. This is the 50th centile; healthy babies commonly vary by about 12.7% either way.1

A reference value, not a measurement of your baby.

How your baby is developing

  • Your baby's arms and legs are now in proportion with the rest of the body.2
  • Around this time, your baby is practicing breathing movements and getting into patterns of sleeping and waking.2
  • Between about 23 and 25 weeks, the bone marrow begins making blood cells and the lower airways of the lungs develop.3
  • Your baby is beginning to store fat, which will gradually help the skin look less wrinkled over the coming weeks.3,4
  • Kicks are likely to get stronger over the next few weeks, and you may start to see your tummy move from the outside.2

Changes you may notice

Everyone’s experience is different. You may notice some of these, or none.

  • Your breasts may start leaking colostrum, an early type of milk. Not everyone notices this during pregnancy.2
  • Some people get rib pain as the rib cage expands to make room for the bump, and you may feel more breathless as the baby presses upward. Resting with your feet up can help; talk to your midwife or doctor if you're worried.2
  • Other common symptoms around now include tiredness, backache, heartburn, constipation, leg cramps, swollen hands and feet, and feeling hot.2
  • Your skin may burn more easily in pregnancy, so it helps to use sunscreen and avoid strong midday sun.2

Care around this week

  • Gestational diabetes screening is usually done between 24 and 28 weeks, so it is often discussed around now. In the UK, an oral glucose tolerance test is offered at 24 to 28 weeks if you have a higher chance of gestational diabetes.5,6
  • Get to know your baby's usual pattern of movements. If movements slow down, stop or change, contact your midwife, provider or maternity unit straight away, even at night. Don't wait for your next appointment.7
  • In the UK, if this is your first baby, a midwife appointment is usually offered at 25 weeks.8

Questions to ask your provider

  • Am I likely to be offered the gestational diabetes test, and how does it work?
  • Is my rib pain or breathlessness something to keep an eye on?
  • What signs of early labor should make me call you straight away?
  • Is it okay to use breast pads if I'm leaking colostrum?
When to contact your provider straight away

Call 911 (US) or 999 (UK) in an emergency, such as heavy bleeding or bleeding with severe pain, a seizure, chest pain, or severe trouble breathing.10,11,12,13

These symptoms are not always serious, but each one needs prompt advice from your provider, midwife or maternity unit (or NHS 111 in the UK if you cannot reach them) rather than waiting for your next appointment, and it helps to tell them you are pregnant.

  • Vaginal bleeding or spotting at any stage of pregnancy. Call 911 or 999 if the bleeding is heavy or comes with severe belly pain, shoulder pain, or feeling faint or dizzy.12,14
  • Fluid leaking or gushing from your vagina, or discharge that is unusual for you. Get checked straight away if the fluid is greenish, colored or smells bad.9,12,13,15
  • Your baby moving less than usual, not moving, or a change in their usual pattern of movements. Call immediately, even in the middle of the night, and do not use a home Doppler to check yourself.7,12
  • A severe headache that does not go away with simple painkillers or gets worse, or sudden changes in your vision such as blurring or seeing flashing lights.10,12,13
  • Sudden swelling of your face, hands or feet, or swelling, redness or pain in a leg.10,12,13
  • Belly pain that is severe or does not go away after resting, or pain just below the ribs.10,12,16
  • Regular tightenings or contractions, period-type pains, or backache that is unusual for you before 37 weeks, which can be signs of preterm labor.9,16
  • A fever of 100.4°F (38°C) or higher, or feeling hot, cold or shivery.9,12,13
  • Shortness of breath that comes on suddenly or happens when you lie flat, chest pain, a racing or pounding heart, or dizziness or fainting.12,13
  • Very itchy skin, especially on the palms of your hands or soles of your feet, or itching that is worse at night.17
  • Being sick so often that you cannot keep food or drink down, or signs of dehydration such as dark urine, peeing very little, or feeling dizzy.12,18
  • Thoughts of harming yourself or your baby. Get help right away, and call 911 or 999 if you think you might act on them.12,19

Questions about 23 weeks

Is it normal to leak colostrum at 23 weeks?

Yes, some people's breasts start leaking colostrum, an early form of milk, around this time. Others don't notice any leaking during pregnancy.2

Why do my ribs hurt at 23 weeks pregnant?

Your rib cage expands to make room for the growing bump, and the baby can press upward, which can cause rib pain and breathlessness. Resting with your feet up may help, and your midwife or doctor can advise if you're worried.2

What are the signs of premature labor?

Signs before 37 weeks include regular contractions or tightenings, period-type pains, a gush or trickle of fluid from the vagina, or backache that's not usual for you. If you notice any of these, contact your maternity unit or provider straight away.9

Sources

  1. In utero analysis of fetal growth: a sonographic weight standardRadiology 181(1):129–133, 1991
  2. 23 weeks pregnant guideNHS Best Start in Life
  3. Fetal developmentUS National Library of Medicine
  4. Fetal development: stages of growthCleveland Clinic
  5. Practice Bulletin No. 190: Gestational Diabetes MellitusAmerican College of Obstetricians and Gynecologists, 2018
  6. Gestational diabetesNHS (England)
  7. Your baby's movementsNHS (England)
  8. Your antenatal appointmentsNHS (England)
  9. Premature labour and birthNHS (England)
  10. Pre-eclampsiaNHS (England)
  11. Epilepsy and pregnancyNHS (England)
  12. Urgent Maternal Warning Signs and Symptoms (Hear Her campaign)US Centers for Disease Control and Prevention
  13. Pregnancy symptoms you need to get help forNHS (England)
  14. Vaginal bleeding in pregnancyNHS (England)
  15. Signs of going into labourNHS Best Start in Life
  16. Stomach pain in pregnancyNHS (England)
  17. Itching in pregnancyNHS (England)
  18. Severe vomiting in pregnancyNHS (England)
  19. Depression in pregnancyNHS (England)

Links checked November 12, 2026. Citing a source does not mean it endorses this site.

Written from the sources above and checked against them on 2026-11-12. Not reviewed by a clinician. Our editorial policy