The comparison table between fetal size and gestational age is as follows:

At the end of the 12th week, the fetal length is 9cm, the top-to-rump length is 6-7cm, and the weight is 14g.

At the end of 16th week, the fetus is 16cm long, 12cm long from crown to rump, and weighs 110g.

At the end of the 20th week, the fetus is 25cm long, 16cm long from crown to rump, and weighs 320g.

At the end of the 24th week, the fetus was 30cm long, 21cm long from crown to rump, and weighed 630g.

At the end of the 28th week, the fetus was 35cm long, 25cm long from crown to rump, and weighed 1,000g.

At the end of the 32nd week, the fetus is 40cm long, 28cm long at the crown and rump, and weighs 1700g.

At the end of the 40th week, the fetus is 50cm long, 36cm long from crown to rump, and weighs 3400g.

How to estimate baby size by weeks of pregnancy:

If the menstrual cycle is relatively regular, the number of weeks of pregnancy is generally calculated from the first day of the last menstrual period. As the gestational age increases, the fetus will also grow larger and larger. In the early stages of pregnancy, the size of the gestational sac is generally used to determine the gestational age.

From the 10th week of pregnancy, the fetus has basically differentiated and matured, and its appearance has begun to take on a human shape. You can judge whether it is consistent with the gestational age by measuring various indicators of the fetus. The more commonly used indicators are biparietal diameter, head circumference, abdominal circumference, femoral length, etc., as well as fetal length, weight and other indicators estimated based on these.