7 weeks pregnant
The embryo is about 1 cm long; CRL measurement pins down your pregnancy week.
By week 7, the embryo reaches about 1 cm in length. The crown–rump length (CRL) measurement shows your pregnancy week to within a few days.
This week’s ultrasound image
Expected ultrasound appearance and measurements at week 7 (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
20 mm
Crown–rump length
10 mm
Heart rate
132 bpm
How big is your baby this week?
About the size of a blueberry
What can be seen on the ultrasound?
The embryo measures 7–10 mm and is curled into a C shape, with the head appearing larger than the body. A thin membrane (the amnion) can be seen around it. The heart rate is about 120–140 beats per minute.
Your baby’s development
The embryo is about the size of a blueberry. The different parts of the brain are forming, and the arm and leg buds are lengthening. The heart is developing towards its four-chambered structure.
Changes in your body
Increased saliva, a metallic taste in the mouth, strong sensitivity to smells and tiredness are common. Light spotting may occur.
Check-ups at this stage
- CRL measurement to determine the pregnancy week and estimated due date
- Completing first-trimester blood tests
- Urine test (urinalysis)
Tips for this week
- Take short rest breaks during the day
- Eat a diet rich in iron and protein
- A gentle 30-minute walk each day can help
When should you see your doctor?
Contact your doctor if you have bleeding as heavy as or heavier than a period, pass clots, or have severe cramping.
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
What is CRL and why is it measured?
CRL (crown–rump length) is the length of the embryo from the top of the head to the bottom. In the first trimester, it is the most accurate way to determine the pregnancy week.
Does the baby move at 7 weeks?
Movements cannot yet be seen even on ultrasound at this stage; the first small movements start to become visible around week 8.
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