34 weeks pregnant
Your baby is about 45 cm and 2.1 kg; the lungs are maturing.
By week 34, your baby’s lungs are largely mature. Most babies born after this week adapt well with a little support.
This week’s ultrasound image
Expected ultrasound appearance and measurements at week 34 (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)
44.8 cm
Head diameter
87 mm
Head circumference
312 mm
Femur length
65 mm
Estimated weight
2146 g
Heart rate
135 bpm
UA PI
0.86
How big is your baby this week?
About the size of a cantaloupe melon
What can be seen on the ultrasound?
BPD is about 87 mm, HC about 312 mm, AC about 302 mm and FL about 65 mm. Your baby’s position and the amniotic fluid are assessed.
Your baby’s development
Your baby is about the size of a cantaloupe melon. The protective coating on the skin (vernix) thickens. The central nervous system continues to mature.
Changes in your body
Tiredness, difficulty sleeping and pelvic pressure increase. Your vision may be temporarily blurred; if it persists, tell your doctor.
Check-ups at this stage
- Routine check: blood pressure, weight, urine
- Checking your baby’s position
- Discussing the type of birth and your birth plan
Tips for this week
- Plan how you will get to the hospital
- Practise breathing techniques for labour
- Get the nursery and car seat ready
When should you see your doctor?
Seek care straight away if you have reduced baby movements, 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
Will a baby born at 34 weeks be healthy?
Most babies born at this stage adapt well, although they may need neonatal monitoring and help with feeding and keeping warm for a while.
When is the choice between vaginal birth and caesarean made?
The type of birth is planned together with your doctor, based on your baby’s position, the location of the placenta, and your and your baby’s health.
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