Pregnancy › Week by Week › Week 23
At 23 weeks your baby is about the size of a large mango, filling out steadily and getting stronger by the day as the lungs quietly do the slow work of preparing to breathe.
Size
A large mango
head to heel
Length
11.4 in
about 28.9 cm
Weight
1.1 lb
about 501 g
Your baby at 23 weeks
The lungs are laying the groundwork to breathe, and your baby is putting on the weight that will smooth out that thin, translucent skin.
This is a week of steady, purposeful development. Nothing dramatic is being built from scratch, but the systems your baby will one day need to live outside the womb are maturing on their own schedule, and the lungs are the headline.
Lungs. Tiny blood vessels are forming in the lungs and moving toward the air sacs, an early step in learning to exchange oxygen. The lungs are still a long way from ready, but the scaffolding for breathing is going up now.
Skin and body. Your baby’s skin is still thin and a little see through, with a pink or reddish tone because the blood vessels sit close to the surface. That will change as fat fills in underneath over the coming weeks, softening and rounding everything out.
Hearing. Hearing is strong now, and your baby is growing used to the everyday soundtrack of your body: your heartbeat, your voice, the rush of blood. Loud or sudden noises may prompt a little startle you can sometimes feel.
How big is your baby at 23 weeks?
About 11.4 inches (28.9 cm) head to heel and just over a pound (501 g).
From around week 20 your baby is measured head to heel rather than crown to rump, because the legs have stretched out and can be measured in full. The numbers are averages, so a healthy baby can sit comfortably above or below them.
Your body at 23 weeks
Movements are firmer and more regular now, and a bigger bump is starting to shift your balance and your sleep.
Those flutters have grown into real kicks and rolls, and many people start to notice a loose pattern to them, more active at certain times of day, quieter at others. You may also feel occasional tightenings across your bump, known as Braxton Hicks, which are your uterus practicing. They are usually irregular and painless and ease when you change position.
As your bump grows, your center of gravity moves and everyday things like standing up, rolling over, and finding a comfortable sleeping position get trickier. A good pregnancy pillow tucked between your knees and under your bump can make side sleeping far more comfortable. Swelling in your feet and ankles, mild backache, and the odd twinge of round ligament pain are all common company this week.
What is normal, and when to call your provider
Braxton Hicks and mild aches are normal, but call your doctor or midwife the same day if you have any of these:
- Heavy bleeding, or any bleeding with pain
- Severe or persistent abdominal pain, or regular tightenings that grow closer together and do not ease
- A fever over 100.4°F (38°C)
- A severe headache with vision changes, or sudden swelling of the face and hands, which can be signs of pre-eclampsia
- Fluid leaking or a gush from the vagina
- Pain or burning when you urinate
- A noticeable drop in your baby’s usual movement once you have come to know its pattern
Your week 23 checklist
- Keep taking your prenatal vitamin every day
- Start getting to know your baby’s movement pattern, without formal counting yet
- Rest your feet up when you can, and stay hydrated to ease swelling
- If sleep is getting harder, try side sleeping with a pregnancy pillow
- It is a lovely time to start planning where your baby will sleep, a bassinet is an easy first decision
Appointments and tests around 23 weeks
This is usually a quieter stretch between the anatomy scan and the glucose screening, with a routine checkup around now.
At your regular visit your provider will check your blood pressure, your weight, and the growth of your bump by measuring your fundal height, and will likely listen to your baby’s heartbeat. The glucose screening for gestational diabetes is coming up soon, usually between 24 and 28 weeks; you can read what to expect on our 24 weeks guide. If you have any questions about movement, sleep, or how you are feeling, this visit is a good place to raise them.
You may hear the word viability around this stage. Around 23 to 24 weeks, a baby born early may survive with intensive care in a neonatal unit, though outcomes improve significantly with each additional week in the womb. For the vast majority of pregnancies this is simply a milestone that passes quietly. If you ever have concerns about preterm labor, your provider is the right person to talk to, and reaching out early is always the right call.
A few things worth having on hand now
A note for your partner
The kicks are strong enough now that you can often feel them from the outside. Rest a hand on the bump in the evening when the baby tends to be active and wait. It is one of the first ways you get to say hello directly, and it means a lot to share those quiet moments together.
You are not alone this week
Reading about viability can stir up big feelings, and that is completely understandable. For nearly everyone this is just a number that comes and goes on the way to a full term birth. Be gentle with yourself, lean on your provider with any worry, and let the small joys, the kicks, the planning, the daydreaming, have their place too.
23 weeks pregnant, common questions
What does viability mean at 23 weeks?
Viability refers to the point at which a baby has a chance of surviving outside the womb with medical support. Around 23 to 24 weeks is often described as the edge of viability, and while babies born now may survive with intensive neonatal care, every additional week inside significantly improves the outlook. For most pregnancies this milestone simply passes on the way to a full term birth.
How often should I feel my baby move?
By now most people feel regular movement, and your baby will settle into a loose pattern of active and quiet times. There is no need for formal kick counting yet, but it helps to get familiar with what is normal for you. If you ever notice a clear drop from that usual pattern, contact your provider the same day.
Is it too early to buy a bassinet or plan the nursery?
Not at all. The second trimester is a comfortable time to make early decisions like where your baby will sleep, with energy and time still on your side. Choosing a bassinet now takes one thing off your list for later, and enjoying the planning is part of the fun.
What are Braxton Hicks contractions?
They are irregular, usually painless tightenings across your bump as your uterus practices for labor. They tend to come and go, do not grow closer together, and often ease when you move or drink water. Regular tightenings that build in strength or frequency are different, so call your provider if that happens.
Sources
- American College of Obstetricians and Gynecologists (ACOG), Periviable Birth and second trimester care guidance.
- Mayo Clinic, Fetal development: the 2nd trimester, and Premature birth.
- MedlinePlus, National Library of Medicine (NIH), Fetal development and prenatal care.
Medical disclaimer: This page is for information and education only and is not a substitute for professional medical advice. Every pregnancy is different. Always follow the guidance of your doctor, midwife, or qualified provider, and contact them with any concerns.