37 weeks pregnant
Your pregnancy reaches term; your baby is about 48 cm and 2.9 kg.
From week 37, your pregnancy is considered ‘early term’. Your baby is almost ready to be born.
This week’s ultrasound image
Expected ultrasound appearance and measurements at week 37 (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)
48 cm
Head diameter
92 mm
Head circumference
328 mm
Femur length
70 mm
Estimated weight
2859 g
Heart rate
134 bpm
UA PI
0.8
How big is your baby this week?
About the size of a bunch of Swiss chard
What can be seen on the ultrasound?
BPD is about 92 mm, HC about 328 mm, AC about 328 mm and FL about 70 mm. The estimated weight is around 2,900 grams.
Your baby’s development
Your baby is about the length of a bunch of Swiss chard. The lungs, brain and digestive system are getting ready for life outside. Sucking, swallowing and grasp reflexes are strong.
Changes in your body
Pelvic pressure, lower back pain and irregular tightenings increase. The mucus plug that seals the cervix may come away.
Check-ups at this stage
- Weekly check: blood pressure, weight, urine
- NST and ultrasound if needed
- Finalising your birth plan
Tips for this week
- Keep your phone charged and your bag ready
- Take gentle walks and rest
- Learn to track how often your contractions come and how long they last
When should you see your doctor?
Go to the hospital if your waters break, or if you have bleeding, regular contractions every 5 minutes, reduced baby movements, 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
What does full term mean?
Births between 37+0 and 41+6 weeks are considered term. Weeks 37–38 are called early term, and weeks 39–40 full term.
Does losing the mucus plug (show) mean labour has started?
No. Pink or brownish mucus can mean labour is getting closer, but it may start hours or days later. If you have heavy bleeding, seek care straight away.
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