Fetal Growth Chart: Weekly Baby Length and Weight
How big is your baby each week during pregnancy? Doctors monitor your baby’s growth with ultrasound scans and fundal height checks. The growth chart below provides an idea of your baby’s size, though it’s important to remember that each baby is unique, and growth rates can vary based on factors like your height, weight, ethnicity, and prior pregnancies. In India, newborns tend to be slightly smaller than the global average.
How is fetal growth measured?
Your baby’s growth is tracked at each ultrasound scan.
From 8 to 13 weeks of pregnancy, your baby’s size is measured from head to bottom (crown to rump length or CRL) as the legs are curled up. After 13 weeks, measurements shift to head to foot (crown to heel) until birth.
In between ultrasounds, doctors also measure your fundal height—how high your womb has risen in your abdomen—to ensure your baby is growing as expected for your pregnancy stage.
Not sure how far along you are in your pregnancy? Check out our pregnancy timing guide for details on how weeks are counted, or use our pregnancy due date calculator to estimate your due date.
Using the Fetal Growth Chart
The chart below provides an average length and weight for your baby from 8 weeks through to birth. Keep in mind that every baby grows at a different rate, especially after the first trimester. Your baby's growth can be influenced by factors like your BMI, ethnicity, and whether you've had babies before. Boys typically tend to be longer and heavier than girls, but we’ve averaged these measurements to keep it simple.
It’s also important to note that in India, newborns tend to be smaller than the global average, with an average birth weight between 2.5kg and 4kg and a length between 48cm and 52cm.
Fetal Growth Chart: 8 to 13 Weeks
The lengths listed below are measured from head to bottom (crown to rump).
| Pregnancy Week | Average Length (cm) | Average Weight (g) |
|---|---|---|
| 8 weeks | 1.6 cm | 20 g |
| 9 weeks | 2.3 cm | 27 g |
| 10 weeks | 3.1 cm | 35 g |
| 11 weeks | 4.1 cm | 45 g |
| 12 weeks | 5.4 cm | 58 g |
| 13 weeks | 6.7 cm | 73 g |
Fetal Growth Chart: 14 to 41 Weeks
From 14 weeks onward, measurements are from head to foot (crown to heel).
| Pregnancy Week | Average Length (cm) | Average Weight (g) |
|---|---|---|
| 14 weeks | 14.7 cm | 93 g |
| 15 weeks | 16.7 cm | 117 g |
| 16 weeks | 18.6 cm | 146 g |
| 17 weeks | 20.4 cm | 181 g |
| 18 weeks | 22.2 cm | 223 g |
| 19 weeks | 24 cm | 273 g |
| 20 weeks | 25.7 cm | 331 g |
| 21 weeks | 27.4 cm | 399 g |
| 22 weeks | 29 cm | 478 g |
| 23 weeks | 30.6 cm | 568 g |
| 24 weeks | 32.2 cm | 670 g |
| 25 weeks | 33.7 cm | 785 g |
| 26 weeks | 35.1 cm | 913 g |
| 27 weeks | 36.6 cm | 1.1 kg |
| 28 weeks | 37.6 cm | 1.2 kg |
| 29 weeks | 39.3 cm | 1.4 kg |
| 30 weeks | 40.5 cm | 1.6 kg |
| 31 weeks | 41.8 cm | 1.8 kg |
| 32 weeks | 43 cm | 2 kg |
| 33 weeks | 44.1 cm | 2.2 kg |
| 34 weeks | 45.3 cm | 2.4 kg |
| 35 weeks | 46.3 cm | 2.6 kg |
| 36 weeks | 47.3 cm | 2.8 kg |
| 37 weeks | 48.3 cm | 3 kg |
| 38 weeks | 49.3 cm | 3.2 kg |
| 39 weeks | 50.1 cm | 3.4 kg |
| 40 weeks | 51 cm | 3.6 kg |
| 41 weeks | 51.8 cm | 3.8 kg |
What If My Baby’s Size Doesn’t Match the Expected Growth?
Your doctor will only be concerned if your baby’s growth deviates by more than two weeks from the expected measurements. If your baby is significantly smaller or larger, it could indicate potential growth concerns, such as intrauterine growth restriction (IUGR) or accelerated growth due to conditions like gestational diabetes.
If there’s a concern, your doctor will recommend additional tests and scans to diagnose the cause and ensure your baby receives the proper care for healthy growth.
This fetal growth chart offers a general guideline, but remember that each pregnancy is unique. Always follow your healthcare provider's advice and attend all scheduled checkups to ensure the best outcomes for you and your baby.
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