Fetal Development 24 Weeks | Inside The Second Trimester

Reaching week 24 can feel like a turning point. You know your baby’s routines a little better, kicks show up more often, and many parents start to picture what life will look like once they meet this new person. At the same time, questions about how the baby is growing and what this week really means are completely normal.

This guide walks through what is happening with growth at 24 weeks, how your own body may feel, and which signs call for medical help. You will see where this week fits in the bigger arc of pregnancy and how small daily choices can keep both you and the baby as healthy as possible.

Fetal Development 24 Weeks: Milestones And Symptoms

Week 24 sits near the end of the second trimester. Many parents notice that baby movements are stronger and easier to track. Health care teams also start to talk more about topics such as gestational diabetes screening and birth planning, because the third trimester is not far away.

From a growth point of view, this week brings two big ideas. First, the baby now has many features that resemble a newborn, including a defined face, fingers, toes, and outside genitalia. Second, major organs such as the lungs and brain are busy building structure and connections so they can work well after birth. The baby still needs many more weeks in the uterus for those systems to mature.

Parents often hear that this is the stage when survival outside the uterus becomes possible in some cases. That concept, sometimes called viability, depends on many factors, including birth weight, gestational age, and access to advanced neonatal care. National groups such as the NICHD pregnancy factsheet explain that by this stage the baby shows clearer sleep and wake cycles and already has footprints and fingerprints.

Where Week 24 Fits In The Second Trimester

Pregnancy care teams usually divide pregnancy into three parts, called trimesters. Week 24 falls in months five to six, when many people notice a bit more energy than in early pregnancy but also more physical strain from a growing uterus. The second trimester also covers the time when many parents first feel kicks and hear more details about anatomy from ultrasound visits.

Medical groups such as the Mayo Clinic fetal development overview describe this trimester as a time when movement, hearing, and facial features become more distinct. At week 24, each of these areas has reached a new stage, yet the baby still has a lot of growing to do.

Baby’s Size And Growth At 24 Weeks

By week 24, many sources describe the baby as about the size of an ear of corn. Medical references note that length from crown to rump often falls a little above eight inches, with total length from head to heel close to twelve inches. Weight commonly lands between one and one and a half pounds, though every baby follows a slightly different plot on the growth chart.

An infographic from the American College Of Obstetricians And Gynecologists notes that by the end of week 24 the fetus measures around twelve inches and weighs about one and a half pounds. This size gives enough room to move actively while still leaving space in the uterus for plenty of amniotic fluid.

Length, Weight, And Proportions

The head still takes up a larger share of body length than it will at birth, yet the rest of the body is catching up. Limbs are more filled out, and muscles gain strength, which you feel as firmer jabs and rolls. Fat stores are still modest, so the skin looks thin and slightly wrinkled on ultrasound images. Over the next several weeks, fat will build under the skin and round out the baby’s outline.

Visible Changes On Ultrasound

A detailed scan at this stage often shows open nostrils, eyelids, and developing eyebrows and hair. Some parents notice that facial expressions change during a scan. Movements such as sucking, yawning, or stretching can appear, and hands may reach toward the face. These motions come from growing muscle strength and from brain pathways that are forming patterns of activity.

Area Of Development	What Happens Around 24 Weeks	Why It Matters Later
Brain	Rapid growth, more folds on the surface, stronger sleep and wake cycles.	Lays groundwork for later thinking, movement control, and sensory processing.
Lungs	Air sacs form and early surfactant production begins.	Helps the lungs expand and exchange oxygen after birth.
Skin	Still thin and reddish, covered with vernix and fine hair.	Vernix protects the skin from constant contact with amniotic fluid.
Senses	Hearing sharpens; baby responds to sound and light more clearly.	Helps bonding through voices and helps develop sleep patterns.
Immune System	More white blood cells begin to form.	Prepares the body to fight infection in the newborn period.
Digestive Tract	Baby swallows fluid and passes small amounts of meconium.	Practices motions needed for feeding and digestion after birth.
Movement	Stronger kicks, rolls, and stretches occur throughout the day.	Shows muscle growth and gives clues about general well-being.

Brain, Senses, And Sleep Patterns

At this stage the brain grows quickly, adding new layers and folds. Nerve cells form trillions of connections that lay groundwork for later learning and behavior. While that process will continue for years after birth, week 24 marks a time when many major brain structures are in place.

Hearing has reached a point where the baby can react to sound with movement or changes in heart rate. Research summaries from the National Institute Of Child Health And Human Development point out that during the second trimester the fetus starts to respond to outside noise and develops more regular sleep cycles. You might notice patterns in when kicks happen most often, such as after meals or when you lie down.

Touch, Taste, And Sight

Touch input grows as the baby brushes hands against the face, sucks fingers, and presses feet against the uterine wall. Taste buds on the tongue get more sensitive, and small amounts of amniotic fluid carry flavor from the foods you eat. Eyes remain closed much of the time, yet they can already sense changes in light through the uterus and abdominal wall.

These senses do more than give simple input. They also help the nervous system practice coordinating muscles. Repeated motions, such as swallowing fluid or bringing hands to the mouth, train pathways that will help with feeding and calming later.

Lung Development And The Question Of Viability

Many parents wonder how close their baby is to being able to breathe on their own. Around week 24, lung tissue contains tiny air sacs and starts to make surfactant, a slippery substance that keeps those sacs from collapsing. Even so, the lungs are still immature, and babies born this early need intense respiratory care.

Health services such as the NHS week 24 pregnancy guide describe this week as a point when survival outside the uterus becomes medically possible in some settings. Survival chances depend on gestational age down to the day, birth weight, access to neonatal intensive care, and whether there are other health problems. Even when survival is possible, the risk of long term complications remains high at this gestational age.

What Happens If Preterm Birth Threatens At 24 Weeks

If signs of early labor appear around this time, your care team may offer steroid injections to help the lungs mature more quickly, along with medicines that try to delay birth. You may be moved to a hospital with an advanced neonatal unit so that newborn specialists are ready if delivery cannot be postponed.

Every situation is different, and decisions about care can feel complex and emotional. In these moments, detailed conversations with clinicians who know you and your pregnancy provide the best guidance for you and your baby.

Your Body At 24 Weeks Pregnant

While fetal development takes center stage in many parents’ minds, your own body is working hard. The uterus now reaches close to the level of the belly button or above, and weight gain often becomes more noticeable. As the uterus grows, ligaments stretch, which can cause brief, sharp twinges on one or both sides of the lower abdomen.

Common symptoms this week include heartburn, mild swelling in the ankles by the end of the day, and occasional tightening of the uterus known as Braxton Hicks contractions. These tightening episodes usually remain irregular and fade with rest or hydration. If they become regular, painful, or are paired with bleeding or fluid leakage, call your maternity unit or health care provider right away.

Sleep, Mood, And Daily Comfort

Finding a comfortable sleep position may take more effort than earlier in pregnancy. Many clinicians suggest resting on your side with a pillow between your knees and another under the belly. Short walks, stretching, and gentle prenatal exercise classes can ease back strain and help manage stiffness.

Mood can shift more at this stage as hormones change and the reality of parenthood feels closer. Talking openly with partners, friends, or a trusted professional about worries and hopes can ease stress. If low mood, anxiety, or intrusive thoughts start to interfere with daily tasks, tell your health care team so they can connect you with extra help.

Sign Or Symptom	Often Part Of Week 24	Contact A Clinician If
Light, irregular tightening of the uterus	Comes and goes, eases with rest or fluids.	Becomes regular, painful, or closer than every ten minutes.
Mild ankle or foot swelling by evening	Improves overnight or with leg elevation.	Sudden swelling in hands, face, or around the eyes.
Lower back ache	Linked with activity, improves with rest and stretching.	Comes with fever, burning while urinating, or rhythmic cramps.
Vaginal discharge	Thin or milky with mild smell.	Becomes watery like a gush, bloody, or foul smelling.
Baby movements	Felt on most days, stronger over time.	You feel fewer movements than usual or none at all.
Headache	Occasional and mild.	Severe, sudden, or paired with vision changes.

Habits That Encourage Healthy Growth At 24 Weeks

Daily routines can make a real difference to comfort and health for both parent and baby at this stage. A balanced eating pattern with a mix of fruits, vegetables, whole grains, protein, and healthy fats provides building blocks for organs and tissues. Many clinicians also recommend regular sources of iron and calcium, along with prenatal vitamins if prescribed.

Staying active within the limits of your own body brings benefits for circulation, mood, and sleep. Short walks, swimming, and prenatal yoga classes designed for pregnancy are common choices. Before starting new workout plans, check with the clinician who manages your prenatal care, especially if you have medical conditions such as high blood pressure or diabetes.

Prenatal Visits Around Week 24

Many people attend a routine prenatal visit near this time. Topics often include blood pressure checks, urine tests for protein or sugar, measurement of uterine height, and a review of symptoms. In many regions this is also close to the time when screening for gestational diabetes takes place, usually between weeks 24 and 28, using a glucose drink and blood tests.

Bring questions about movements, work, travel, birth preferences, or anything else on your mind. Writing notes beforehand helps make the most of the visit and makes it easier to recall what you wanted to talk about.

When To Call Your Health Care Provider

While many pregnancies progress without major complications, week 24 is a time to stay alert to warning signs. Call your maternity unit, midwife, or doctor urgently or seek emergency care if any of these situations occur:

• Vaginal bleeding, a gush of fluid, or a steady trickle that may suggest ruptured membranes.
• Strong, regular contractions or constant lower back pain that does not ease with rest.
• Severe abdominal pain, chest pain, or shortness of breath.
• Sudden swelling of the face, hands, or around the eyes, or a pounding headache with visual changes such as flashing lights.
• Fever, chills, or burning during urination.
• A clear change in baby movements, especially if you feel fewer movements than usual.

Trust your instincts. If something feels wrong, contacting a clinician is always reasonable, even if you are not sure whether a symptom is serious. Early assessment can catch problems before they grow larger.

What Comes After 24 Weeks

From week 24 onward, growth continues at a steady pace. The baby will add fat and muscle, the lungs will mature, and the brain will keep forming complex networks. Many parents use the weeks between now and the third trimester to line up childcare plans, think through feeding choices, and prepare their home for the new arrival.

Routine care, shared decision making with your health team, and attention to rest, food, and movement give your baby a strong start. Understanding what fetal development looks like at 24 weeks can make each kick and flutter feel even more meaningful as the due date draws closer.