At 13 weeks of gestation: the mean biparietal diameter was 2.52 and 0.25, the mean abdominal circumference was 6.90 and 1.65, and the mean femoral length was 1.17 and 0.31.
At 14 weeks of gestation: the mean biparietal diameter was 2.83 and 0.57, the mean abdominal circumference was 7.77 and 1.82, and the mean femoral length was 1.38 and 0.48.
15 weeks of gestation: the mean biparietal diameter was 3.23 and 0.51, the mean abdominal circumference was 9.13 and 1.56, and the mean femoral length was 1.74 and 0.58.
16 weeks of gestation: the mean biparietal diameter was 3.62 and 0.58, the mean abdominal circumference was 10.32 and 1.92, and the mean femoral length was 2.10 and 0.51.
17 weeks of gestation: the mean biparietal diameter was 3.97 and 0.44, the mean abdominal circumference was 11.49 and 1.62, and the mean femoral length was 2.52 and 0.44.
18 weeks of gestation: the mean biparietal diameter was 4.25 and 0.53, the mean abdominal circumference was 12.41 and 1.89, and the mean femoral length was 2.71 and 0.46.
19 weeks of gestation: the mean biparietal diameter was 4.52 and 0.53, the mean abdominal circumference was 13.59 and 2.30, and the mean femoral length was 3.03 and 0.50.
20 weeks of gestation: the mean biparietal diameter was 4.88 and 0.58, the mean abdominal circumference was 14.80 and 1.89, and the mean femoral length was 3.35 and O.47.
21 weeks of gestation: the mean biparietal diameter was 5.22 and 0.42, the mean abdominal circumference was 15.62 and 1.84, and the mean femoral length was 3.64 and 0.40.
22 weeks of gestation: the mean biparietal diameter was 5.45 and 0.57, the mean abdominal circumference was 16.70 and 2.23, and the mean femoral length was 3.82 and 0.47.
23 weeks of gestation: the mean biparietal diameter was 5.80 and 0.44, the mean abdominal circumference was 17.90 and 1.85, and the mean femoral length was 4.21 and 0.41.
At 24 weeks of gestation: the mean biparietal diameter was 6.05 and 0.50, the mean abdominal circumference was 18.74 and 2.23, and the mean femoral length was 4.36 and 0.51.
At 25 weeks of gestation: the mean biparietal diameter was 6.39 and 0.70, the mean abdominal circumference was 19.64 and 2.20, and the mean femoral length was 4.65 and 0.42.
At 26 weeks of gestation: the mean biparietal diameter was 6.68 and 0.61, the mean abdominal circumference was 21.62 and 2.30, and the mean femoral length was 4.87 and O.41.
At 27 weeks of gestation: the mean biparietal diameter was 6.98 and 0.57, the mean abdominal circumference was 21.81 and 2.12, and the mean femoral length was 5.10 and 0.41.
At 28 weeks of gestation: the mean biparietal diameter was 7.24 and the mean abdominal circumference was 22.86 and 2.41, and the mean femoral length was 5.35 and 0.55.
29 weeks of gestation: the mean biparietal diameter was 7.50 and the mean abdominal circumference was 23.71 and 1.50. The mean femoral length was 5.61 and 0.44.
30 weeks of gestation: the mean biparietal diameter was 7.83 and 0.62, the mean abdominal circumference was 24.88 and 2.03, and the mean femoral length was 5.77 and 0.47.
31 weeks of gestation: the mean biparietal diameter was 8.06 and 0.60, the mean abdominal circumference was 25.78 and 2.32, and the mean femoral length was 6.03 and 0.38.
32 weeks of gestation: the mean biparietal diameter was 8.17 and 0.65, the mean abdominal circumference was 26.20 and 2.33, and the mean femoral length was 6.43 and 0.49.
33 weeks of gestation: the mean biparietal diameter was 8.50 and 0.47, the mean abdominal circumference was 27.78 and 2.30, and the mean femoral length was 6.42 and 0.46.
34 weeks of gestation: the mean biparietal diameter was 8.61 and 0.63, the mean abdominal circumference was 27.99 and 2.55, and the mean femoral length was 6.62 and 0.43.
35 weeks of gestation: the mean biparietal diameter was 8.70 and 0.55, the mean abdominal circumference was 28.74 and 2.88, and the mean femoral length was 6.71 and 0.45.
At 36 weeks of gestation, the mean biparietal diameter was 8.81 and 0.57, the mean abdominal circumference was 29.44 and 2.83, and the mean femoral length was 6.95 and 0.47.
37 weeks of gestation: the mean biparietal diameter was 9.00s0.63, the mean abdominal circumference was 30.14s2017, and the mean femoral length was 7.10s0.52.
At 38 weeks of gestation: the mean biparietal diameter was 9.08 and 0.59, the mean abdominal circumference was 30.63 and 2.83, and the mean femoral length was 7.20 and 0.43.
39 weeks of gestation: the mean biparietal diameter was 9.21 and 0.59, the mean abdominal circumference was 31.34 and 3.12, and the mean femoral length was 7.34 and 0.53.
At 40 weeks of gestation, the mean biparietal diameter was 9.28 and the mean abdominal circumference was 31.49 and 2.79, and the mean femoral length was 7.4 and 0.53.
Biparietal diameter: the length of the widest part of the fetus between the left and right sides of the head, also known as the large transverse head diameter. It is often used by doctors to observe the development of the child and to determine whether there is cephalopelvic disproportion and a smooth delivery.
Abdominal circumference: The length of one week of the fetal belly, also known as the abdominal circumference. It is often used by doctors to estimate the development of the fetus together with the anterior-posterior and transverse trunk diameters.
Femoral length: the length of the fetal thigh bone, its normal value is about 2-3 cm difference from the value of the biparietal diameter in the corresponding month of pregnancy, for example, if the biparietal diameter is 8.6 cm, the femoral length should be 6.6 cm.