Welcome to the third trimester Your baby is laying down fat, their ears hear everything you say — and every kick is their way of saying "I'm right here."

Week 28 is an important milestone: you've crossed into the third trimester. About 12 weeks remain until you meet your baby. Your baby is growing fast — gaining nearly half a kilogram per week — and the brain is beginning to form the cortical folds that are a hallmark of the human brain.

This article draws on guidance from WHO [1], ACOG [2], NHS [3], and the Royal Thai College of Obstetricians and Gynaecologists [4]. It covers four key topics for this week: your baby's changes, kick counting, the glucose tolerance test, and anti-D for Rh-negative moms.

Your baby at week 28

Your baby is about 37 centimeters long and weighs approximately 1 kilogram — roughly the size of a young coconut.

What's developing right now:

Brain is beginning to fold and groove (gyrification), which will eventually triple the brain's surface area
Eyes can open partially and respond to light shining through the abdominal wall
Ears are fully developed — your baby hears your voice, your heartbeat, and sounds from outside
Lungs continue developing and are producing surfactant, which prevents the air sacs from collapsing after birth
Fat under the skin is accumulating, making the skin smoother and less translucent
Sucking, swallowing, and startle reflexes are fully in place

Why week 28 matters for survival

Babies born at 28 weeks have a survival rate above 90% in hospitals with a NICU [2]. A lot of careful medical support is still needed, but this milestone reflects how far your baby has come.

Kick counting: the simplest daily check-in

"Count 10 movements" — it's the easiest health check you can do for your baby every single day.

From 28 weeks onwards, ACOG [2] recommends counting your baby's movements daily as a simple, effective way to monitor fetal well-being.

How to count kicks

Choose a time when your baby tends to be active — usually after a meal or in the evening
Lie on your side or sit comfortably — reduce distractions
Count every movement — kicks, jabs, rolls, punches
Goal: 10 movements within 2 hours
Note the time when you reach 10 — track it each day to spot changes in pattern

Understanding the patterns

Babies have sleep-wake cycles; a normal sleep stretch is 20–40 minutes, sometimes up to 90 minutes
Some decrease in movement is normal close to the due date as space gets tighter — but the count should not drop sharply
Caffeine, high sugar, or a heavy meal may temporarily increase movement

Glucose tolerance test: weeks 24–28

The Oral Glucose Tolerance Test (OGTT) screens for gestational diabetes (GDM) and is typically done between weeks 24–28, per the Royal Thai College of Obstetricians and Gynaecologists [4] and ACOG [5].

Why it matters

GDM affects approximately 7–10% of pregnancies in Thailand
Unmanaged GDM raises the risk of a very large baby (macrosomia), difficult delivery, low blood sugar in the newborn, and a higher long-term risk of type 2 diabetes for the mother

What the test involves

Fast for at least 8 hours (water is fine)
First blood draw for fasting glucose
Drink 75 g of glucose solution
Blood draws at 1 hour and 2 hours after drinking
GDM is diagnosed if any one value meets or exceeds the threshold

Anti-D immunoglobulin injection at around 28 weeks (prophylactic dose)
A second injection within 72 hours after delivery if the baby is Rh-positive
Anti-D should also be given after any abnormal bleeding during pregnancy

What to know

Anti-D primarily protects future pregnancies, not the current one — sensitization from this pregnancy would be the problem for the next
The injection is safe for both you and your baby
If you're unsure of your blood type, ask at your antenatal clinic

How your body is changing at week 28

Fundal height is approximately 28 centimeters from the pubic bone — fundal height in centimeters roughly equals gestational age in weeks
Shortness of breath as the uterus pushes up against the diaphragm
Back and pelvic pain from the hormone relaxin and increasing weight
Swollen ankles and feet — especially later in the day, usually normal
Braxton Hicks contractions (irregular, practice contractions) becoming more frequent
Heartburn as the uterus pushes against the stomach
Difficulty sleeping — sleeping on your left side with a pillow between your knees and under your belly helps

When to seek care immediately

Contact your doctor or go to the emergency room if you have any of these:

Reduced fetal movement — fewer than 10 movements in 2 hours, or no movement for more than 2 hours
Any vaginal bleeding, heavy or light
Severe or persistent abdominal pain, or contractions that don't ease
Severe headache, blurred vision, or seeing flashing lights — possible signs of pre-eclampsia
Sudden swelling of the face, hands, or feet, especially with a headache
Fluid or liquid leaking from the vagina — possible amniotic fluid leak
Fever above 38°C (100.4°F)

Summary

Week 28 is a real milestone — your baby is strong, and you're entering the final stretch.

Key actions for this week:

Start counting kicks daily — goal is 10 movements in 2 hours; record the time and make it a habit
Get the glucose tolerance test (OGTT) if you haven't done it during weeks 24–28
Rh-negative moms: ask your doctor about the anti-D injection this week
Rest well — sleep on your left side, reduce long periods of standing
Watch for signs of pre-eclampsia — headache, blurred vision, unusual swelling
Prepare for the third trimester — childbirth classes, a birth plan, and newborn care basics

The third trimester is the final chapter before you meet your baby. Every day that passes, your little one grows stronger. You're doing wonderfully — just a little further now.

Pregnancy Week 28: Third Trimester Begins — Count Those Kicks