The fetus starts to develop from the time of the commencement of the pregnancy. Ultrasound scans are carried out periodically to track the growth of the baby. It helps in the determination of the approximate length and weight of the baby. As the fetus grows in the womb, the size of your bump also increases.
The level of its development isn’t known as the baby is enclosed by the amniotic fluid on all sides. The fetal growth chart of the fetus tells you the weight and length of an average baby starting from two months of pregnancy to the time of its birth.
Why is it important to learn about the length and weight of the fetus?
A baby present in the uterus is mostly measured from crown to rump from eight weeks to nineteen weeks of pregnancy. You will notice a lot of activity in the fetus in the twentieth week of the scan. In addition to the ultrasound scan, your doctor will also check the circumference of the baby’s head and abdomen, and the length of the thigh bone of the fetus. It will provide more clarity and precise details about its development.
Birth charts based on the international guidelines, may not be very accurate for Indian babies. This is because babies who are born in India are normally smaller in size at birth compared to the international average. However, the difference in the weight and height readings will be nominal.
In cases, when the difference in the baby’s development is beyond two weeks for the given stage of pregnancy, then it can be a concern. Your doctor may ask you to ensure that the baby is healthy and the pregnancy is going safe and smooth.
Fetal growth chart: eight to 19 weeks of pregnancy
The lengths below are from head to bottom (crown to rump).
| Pregnancy week | Average Length (cm) | Average Weight (g) |
|---|---|---|
| 8 weeks | 1.6cm | 1g |
| 9 weeks | 2.3cm | 2g |
| 10 weeks | 3.1cm | 4g |
| 11 weeks | 4.1cm | 7g |
| 12 weeks | 5.4cm | 14g |
| 13 weeks | 7.4cm | 23g |
| 14 weeks | 8.7cm | 43g |
| 15 weeks | 10.1cm | 70g |
| 16 weeks | 11.6cm | 100g |
| 17 weeks | 13cm | 140g |
| 18 weeks | 14.2cm | 190g |
| 19 weeks | 15.3cm | 240g |
Fetal growth chart: 20 to 40 weeks of pregnancy
The lengths below are from head to foot (crown to heel).
| Pregnancy week | Average Length (cm) | Average Weight (g) |
|---|---|---|
| 20 weeks | 25.6cm | 300g |
| 21 weeks | 26.7cm | 360g |
| 22 weeks | 27.8cm | 430g |
| 23 weeks | 28.9cm | 501g |
| 24 weeks | 30cm | 600g |
| 25 weeks | 34.6cm | 660g |
| 26 weeks | 35.6cm | 760g |
| 27 weeks | 36.6cm | 875g |
| 28 weeks | 37.6cm | 1kg |
| 29 weeks | 38.6cm | 1.2kg |
| 30 weeks | 39.9cm | 1.3kg |
| 31 weeks | 41.1cm | 1.5kg |
| 32 weeks | 42.4cm | 1.7kg |
| 33 weeks | 43.7cm | 1.9kg |
| 34 weeks | 45cm | 2.1kg |
| 35 weeks | 46.2cm | 2.4kg |
| 36 weeks | 47.4cm | 2.6kg |
| 37 weeks | 48.6cm | 2.9kg |
| 38 weeks | 49.8cm | 3.1kg |
| 39 weeks | 50.7cm | 3.3kg |
| 40 weeks | 51.2cm | 3.5kg |
When is baby’s measurement done in a pregnancy?
The main objective of performing an ultrasound scan is to get an estimation of the gestational age. While performing the scan, it is assumed that the baby is developing at a normal rate, and as per the fetus’s growth chart. The ultrasound scan method helps compute the number of embryonic and fetal structures using different types of fetal calculators and graphs. Here is what type of baby’s measurement is carried out in pregnancy:
- The viability and dating scan happen between six to nine weeks of pregnancy. This is the stage when the baby’s head to rump length will give a precise due date.
- The nuchal translucency scan is carried out between eleven and thirteen weeks of pregnancy.
- The anomaly scan is carried out between eighteen and twenty weeks of pregnancy. In this scan, the doctor computes the varying areas of the body head circumference, abdominal circumference and thigh bone length. As a result of the scan, the doctor gives the gestational age to every part of the baby.
- The growth scan is performed between twenty-eight and thirty-two weeks of pregnancy. It is done to learn about the well-being of the fetus.
- In between the above scans, the doctor may check the fundal height of the expecting mother. This is done by measuring the height that the top region of the uterus reaches the abdomen. This helps in getting an approximate size of the baby and indicates whether he is growing at an expected rate or not. The fundal height in centimeters is around two weeks less or more than the number of weeks you are e pregnant.
Projected Foetal Weight Calculator
The fetal weight calculator enables you to compute the projected fetal weight and percentile of the fetal weight at the stage of delivery. The calculation is based on the different inputs that include the gestational age, humerus, thigh bone length, head circumference, biparietal diameter, and abdominal circumference. The calculated weight of the fetus can be 16% more or less than the average weight.
Foetal Growth Percentile Calculator
This calculator computes the length of the baby compared to the average length. A baby who has above 50 percentile for growth implies that he has an above-average growth rate. A fetus whose growth percentile falls between the tenth and the ninetieth percentile is observed to be normal.
Various inputs are considered to determine this value such as crown-rump length, head circumference, biparietal diameter, femur length and humerus length, fetal pole, gestational sac, yolk sac, projected fetal weight and abdominal circumference.
Conclusion
Thus the baby weekly growth chart is an important tool to assess the growth of your baby at different trimesters of pregnancy. It is a safe way to determine the development rate and overall health and wellness of the baby in the womb.