28 weeks pregnant
The third trimester begins; your baby weighs about 1 kilogram.
Week 28 marks the start of the third trimester. Your baby reaches about 1 kilogram and can open and close their eyes.
This week’s ultrasound image
Expected ultrasound appearance and measurements at week 28 (illustrative, to-scale drawing).
Abbreviations on the screen
- GS
- Gestational sac diameter
- YS
- Yolk sac
- CRL
- Crown–rump length
- NT
- Nuchal translucency
- BPD
- Biparietal diameter (head width)
- HC
- Head circumference
- AC
- Abdominal circumference
- FL
- Femur (thigh bone) length
- EFW
- Estimated fetal weight
- FHR
- Fetal heart rate (beats per minute)
- GA
- Gestational age (weeks + days)
- UA PI
- Umbilical artery Doppler resistance (PI)
Length (head to heel)
37.5 cm
Head diameter
72 mm
Head circumference
263 mm
Femur length
53 mm
Estimated weight
1005 g
Heart rate
139 bpm
UA PI
1
How big is your baby this week?
About the size of an aubergine
What can be seen on the ultrasound?
BPD is about 72 mm, HC about 263 mm, AC about 243 mm and FL about 53 mm. From now on, if needed, umbilical cord Doppler can show how well the placenta is nourishing your baby.
Your baby’s development
Your baby is about the size of an aubergine and weighs about 1 kilogram. The eyelashes have developed, and your baby can open and close their eyes. The dreaming stage of sleep (REM) begins.
Changes in your body
Shortness of breath, passing urine more often, lower back pain and sleeplessness may increase. Check-ups become more frequent.
Check-ups at this stage
- Anti-D injection if you are Rh negative
- Blood count and iron treatment if needed
- Check-ups usually every 2–3 weeks
Tips for this week
- Count your baby’s movements once a day at a quiet time
- Take frequent breaks and drink plenty of water on long journeys
- Start packing your hospital bag
When should you see your doctor?
Seek care straight away if you notice a clear reduction in your baby’s movements, or have bleeding, leaking fluid, regular contractions, a severe headache or blurred vision.
Growth by week
Values are averages; differences of a few days or a few millimetres between babies are normal.
| Pregnancy weeks | Crown–rump length (cm) | Weight (g) |
|---|---|---|
| Week 4 | — | — |
| Week 5 | — | — |
| Week 6 | 4 mm | — |
| Week 7 | 10 mm | — |
| Week 8 | 16 mm | 1 g |
| Week 9 | 23 mm | 2 g |
| Week 10 | 32 mm | 4 g |
| Week 11 | 43 mm | 8 g |
| Week 12 | 55 mm | 14 g |
| Week 13 | 68 mm | 23 g |
| Week 14 | 85 mm | 43 g |
| Week 15 | 100 mm | 70 g |
| Week 16 | 115 mm | 100 g |
| Week 17 | 128 mm | 140 g |
| Week 18 | 140 mm | 190 g |
| Week 19 | 152 mm | 240 g |
| Week 20 | 25.6 cm | 300 g |
| Week 21 | 26.7 cm | 360 g |
| Week 22 | 27.8 cm | 430 g |
| Week 23 | 28.9 cm | 501 g |
| Week 24 | 30 cm | 600 g |
| Week 25 | 31.9 cm | 660 g |
| Week 26 | 33.8 cm | 760 g |
| Week 27 | 35.6 cm | 875 g |
| Week 28 | 37.5 cm | 1005 g |
| Week 29 | 38.8 cm | 1153 g |
| Week 30 | 40 cm | 1319 g |
| Week 31 | 41.3 cm | 1502 g |
| Week 32 | 42.5 cm | 1702 g |
| Week 33 | 43.6 cm | 1918 g |
| Week 34 | 44.8 cm | 2146 g |
| Week 35 | 45.9 cm | 2383 g |
| Week 36 | 47 cm | 2622 g |
| Week 37 | 48 cm | 2859 g |
| Week 38 | 49 cm | 3083 g |
| Week 39 | 50 cm | 3288 g |
| Week 40 | 51 cm | 3462 g |
Frequently asked questions
How do I count my baby’s movements?
At a quiet time, lie on your left side and count the movements. Usually 10 movements within 2 hours are expected; any clear drop from your baby’s usual pattern should be checked straight away.
What is a Doppler ultrasound?
It is an ultrasound method that measures blood flow in the umbilical cord and the baby’s blood vessels. It shows whether the placenta is nourishing your baby well enough.
Your pregnancy care at SoftCare Clinic
Book an appointment with our specialist doctors for your ultrasound check-up and any questions you may have.
The information on this page is for general guidance only and does not replace a medical examination. Measurements are average values; please discuss your own results with your doctor.
Medical content editor: Op. Dr. Şükrü Sanus