Ultrasound Reference Chart Based on IVF Dates to Estimate Gestational Age at 6–9 weeks’ Gestation

Table 4

The Monash Chart. CRL reference table based on true gestational age in an IVF cohort.

CRL (mm)	GA (wks, days)	GA (days)
1.0 mm	6W1D	42.9
1.5 mm	6W1D	43.3
2.0 mm	6W2D	43.7
2.5 mm	6W2D	44.1
3.0 mm	6W3D	44.5
3.5 mm	6W3D	45.0
4.0 mm	6W3D	45.4
4.5 mm	6W4D	45.8
5.0 mm	6W4D	46.2
5.5 mm	6W5D	46.6
6.0 mm	6W5D	47.0
6.5 mm	6W5D	47.4
7.0 mm	6W6D	47.8
7.5 mm	6W6D	48.2
8.0 mm	7W0D	48.6
8.5 mm	7W0D	49.1
9.0 mm	7W0D	49.5
9.5 mm	7W1D	49.9
10.0 mm	7W1D	50.3
10.5 mm	7W2D	50.7
11.0 mm	7W2D	51.1
11.5 mm	7W3D	51.5
12.0 mm	7W3D	51.9
12.5 mm	7W3D	52.3
13.0 mm	7W4D	52.7
13.5 mm	7W4D	53.2
14.0 mm	7W5D	53.6
14.5 mm	7W5D	54.0
15.0 mm	7W5D	54.4
15.5 mm	7W6D	54.8
16.0 mm	7W6D	55.2
16.5 mm	8W0D	55.6
17.0 mm	8W0D	56.0
17.5 mm	8W0D	56.4
18.0 mm	8W1D	56.8
18.5 mm	8W1D	57.3
19.0 mm	8W2D	57.7
19.5 mm	8W2D	58.1
20.0 mm	8W2D	58.5
20.5 mm	8W3D	58.9
21.0 mm	8W3D	59.3
21.5 mm	8W4D	59.7
22.0 mm	8W4D	60.1
22.5 mm	8W5D	60.5
23.0 mm	8W5D	60.9
23.5 mm	8W5D	61.4
24.0 mm	8W6D	61.8
24.5 mm	8W6D	62.2
25.0 mm	9W0D	62.6
25.5 mm	9W0D	63.0
26.0 mm	9W0D	63.4

GA: gestational age, W: weeks, and D: days.