15 weeks pregnant
Your baby is about 10 cm and 70 grams; the window for the quadruple test opens.
At week 15, your baby grows quickly and the bones are getting stronger. The quadruple test and, if needed, amniocentesis can be done from this week.
This week’s ultrasound image
Expected ultrasound appearance and measurements at week 15 (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)
Crown–rump length
100 mm
Head diameter
31 mm
Head circumference
112 mm
Femur length
17 mm
Estimated weight
70 g
Heart rate
154 bpm
How big is your baby this week?
About the size of an apple
What can be seen on the ultrasound?
BPD is about 31 mm, HC about 112 mm and FL about 17 mm. The bones appear bright white on ultrasound. Your baby’s active movements are easy to see.
Your baby’s development
Your baby is about the size of an apple and weighs around 70 grams. Although the eyelids are closed, sensitivity to light is developing. The legs become longer than the arms.
Changes in your body
Nosebleeds and sensitive gums may occur. Some mums-to-be may start to feel gentle flutters in their tummy.
Check-ups at this stage
- Quadruple test (weeks 15–20, if needed)
- Amniocentesis if considered necessary (weeks 15–20)
- Routine check: blood pressure, weight, urine
Tips for this week
- Your need for iron and calcium increases; review your diet with your doctor
- Wear flat, comfortable shoes
- Avoid standing for long periods
When should you see your doctor?
Contact your doctor if you have bleeding, regular abdominal pain or contractions, leaking fluid or a fever.
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 the quadruple test?
It is a screening test that measures four substances in the mother’s blood (AFP, hCG, oestriol and inhibin-A) to calculate the risk of chromosomal conditions and neural tube defects.
Who is offered amniocentesis?
It is carried out on your doctor’s advice when screening tests show a high risk, the ultrasound shows a finding, or there is a risk of a genetic condition.
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