8 weeks pregnant
CRL is about 1.6 cm; the first small movements may be seen on ultrasound.
At week 8, the embryo grows beyond 1.5 cm and the first small movements start to appear on ultrasound. The heart rate is rising quickly.
This week’s ultrasound image
Expected ultrasound appearance and measurements at week 8 (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)
Gestational sac
27 mm
Crown–rump length
16 mm
Estimated weight
1 g
Heart rate
152 bpm
How big is your baby this week?
About the size of a raspberry
What can be seen on the ultrasound?
CRL measures about 14–17 mm. The head becomes more distinct, and the arm and leg buds can be seen. The heart rate is about 150–160 beats per minute. The yolk sac is still visible.
Your baby’s development
Your baby is about the size of a raspberry. Fingers begin to form, and the elbows and knees appear. The eyelids and the first structures of the ears are taking shape.
Changes in your body
For many people, nausea and tiredness are approaching their peak. The breasts grow and veins may become more visible.
Check-ups at this stage
- First-trimester blood tests: full blood count, blood group, TSH, fasting blood sugar, hepatitis B, HIV, syphilis, rubella
- Antibody screening if you are Rh negative
- Blood pressure and weight monitoring
Tips for this week
- Drink 8–10 glasses of water a day
- Wear a comfortable, supportive bra
- If your nausea is severe, ask your doctor about medication
When should you see your doctor?
Excessive vomiting, weight loss, dizziness or dark urine may indicate dehydration; contact your doctor.
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
Does the baby move at 8 weeks?
Yes, small movements may be seen on ultrasound; however, you will not feel them until around weeks 16–20.
What should the heart rate be at 8 weeks?
It is usually between 140 and 170 beats per minute. The heart rate rises until weeks 9–10 and then slowly decreases.
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