24 weeks pregnant: baby size, symptoms and the glucose test

At 24 weeks pregnant, your baby is about the size of an ear of corn or a small cantaloupe: roughly 30 cm (12 inches) head to heel and around 600 g (1 lb 5 oz). The headline change this week is in the lungs, which begin producing surfactant, the substance that lets the tiny air sacs open after birth.

Week 24 is where pregnancy stops being private: the bump is unmistakable, the kicks are hard to ignore, and appointments start to include the glucose screen. Everything below is an average with a wide, healthy range around it, so your own doctor, midwife or national antenatal programme always comes first.

How big is your baby at 24 weeks pregnant?

About the length of an ear of corn — corn on the cob, if that is the phrase you grew up with — or a small cantaloupe, called a rockmelon in Australia. In numbers, roughly 30 cm and about 600 g: near enough 12 inches head to heel, and a little over a pound.

Treat both as approximations. Scan estimates of weight carry a real margin of error either way, and a baby above or below these figures is very often simply a baby of that size; your team watches growth over time, not one number on one day. From here weight gain speeds up, mostly fat laid down under skin that is still thin and wrinkled, like a shirt a size too big.

24 weeks pregnant is how many months?

Pregnancy is counted in gestational weeks, from the first day of your last menstrual period (LMP), not from the day you conceived. Conception usually follows about two weeks later, so at 24 weeks pregnant your baby has actually been growing for roughly 22 weeks. That offset is built into every due date and scan report.

In months, week 24 sits at the end of the fifth month and the start of the sixth: most people say "about five and a half months", and plenty round up to six. You are near the end of the second trimester, with roughly 16 weeks to go. Our pregnancy week-by-week guide covers every week from the first positive test to your due date.

What your baby is doing this week

Week 24 is less about new body parts than about systems being finished and switched on.

• The lungs start making surfactant. This slippery substance coats the air sacs and stops them collapsing shut, which is what makes that first breath possible. Production increases until the end of pregnancy.
• Fat is building under the skin. The skin is still translucent and wrinkled, with vessels visible underneath, but fat is steadily filling it out.
• The inner ear is complete. The part that governs balance has finished forming, so your baby now senses which way is up.
• Hearing is clearly working. Babies respond to sounds now, and respond differently to their mother's voice. Talking, reading or singing is not silly — it genuinely reaches them.
• Practice breathing. Amniotic fluid moves in and out of the lungs, sometimes felt as hiccups — a soft, regular tapping low in the bump.

What you may be feeling at 24 weeks

The easy stretch of the second trimester is handing over to the heavier work of the third. Common around now:

• Strong, obvious movements — kicks and rolls you can sometimes see through your top.
• Backache. A shifting centre of gravity plus hormones that soften your ligaments. Supportive shoes, moving position often and avoiding heavy lifting help most.
• Heartburn. Smaller meals, eating earlier and staying upright afterwards are worth trying. Take nothing for it, herbal or over-the-counter, without asking your doctor, midwife or pharmacist.
• Swollen feet and hands. Mild swelling that builds through the day is common. Sudden swelling of the face or hands is not — see the list below.
• Tingling or numb fingers. Fluid retention can press on the nerve at the wrist, causing carpal tunnel symptoms that are worst overnight. It usually settles after birth; mention it to your midwife.
• Leg cramps at night — sharp calf cramps that wake you, typical from mid-pregnancy on.
• Stretch marks and itchy skin. Pink, red, purple or brown lines depending on your skin tone, fading to silvery ones in time. Whether you get them is mostly genetics.
• A belly button that pops out — harmless, very common, and it goes back afterwards.
• Fatigue returning. More weight, poorer sleep, more blood to circulate. Being tired again is not a step backwards.
• Occasional painless tightenings that come and go. Regular, rhythmic or painful tightening is different — call.

What to do this week

The glucose test. Screening for gestational diabetes is usually offered between 24 and 28 weeks. How it is done varies: sometimes a sugary drink and one blood test for everyone, sometimes an overnight fast with blood taken before and after the drink, and elsewhere it is offered on the basis of risk factors. Your midwife or doctor will tell you what applies where you live.

Being offered it does not mean anyone suspects a problem. Gestational diabetes is common, often causes no symptoms, and is much easier to manage when picked up early. A raised result means a conversation about food, monitoring and follow-up — not that you did anything wrong.

Movements. Many services start asking what your baby's movements are like around now, because you are best placed to notice a change. You do not need to count kicks formally at 24 weeks; structured counting comes much later, once a settled pattern exists. Just get a feel for what is usual for your baby. Once movements are well established, any reduction or change is worth an immediate call, at any hour, however often you have rung.

Antenatal schedules genuinely differ between countries and clinics, so follow your own team rather than any timeline you read online, including this one. Anything you take, prescribed or not, vitamin or herbal, should be cleared with your doctor, midwife or pharmacist first.

Call your doctor or midwife now if you have

Most of what week 24 brings is uncomfortable rather than dangerous. These are different, and none is ever an overreaction:

• Vaginal bleeding, any amount, at any time.
• Severe or persistent abdominal pain, or tightening that turns regular, rhythmic or painful.
• Fluid leaking from the vagina, trickle or gush.
• Fever, chills, or feeling generally unwell.
• A severe headache with visual changes such as flashing lights or blurring, sudden swelling of the face or hands, or pain under the ribs.
• Pain or burning when you urinate, or needing to go far more often than usual.
• Reduced or changed movements, once you are regularly feeling your baby. Never wait until morning.
• Intense itching, particularly on the palms and soles and especially at night.
• Any sudden, severe symptom that frightens you, including painful swelling or redness in one leg.

Whether this pregnancy has felt smooth, or you are carrying anxiety from a loss, or you are doing all of this alone, week 24 is a good moment to be kind to yourself. Nobody can promise how a pregnancy will unfold — but you are always allowed to ask, to ask again, and to call as often as you need.