Table 1.
Prediction equations for growth parameters (in mm) as a function of gestational age (in days)
| Gestational sac (GS): |
| GS = -9.66 + 1.40(GA) |
| R2 = 0.9602 |
| Crown-rump length (CRL): |
| CRL = -9.42 + 1.09(GA) + 0.0281(GA)2 |
| R2 = 0.9682 |
| Biparietal diameter (BPD): |
| BPD = 50.47 - 17.14(GA) + 2.07(GA)2 - 0.103(GA)3 + 0.00186(GA)4 |
| R2 = 0.9733 |
| Abdominal circumference (AC): |
| AC = -55.75 + 7.52(GA) - 0.166(GA)2 |
| R2 = 0.9723 |
| Femur length (FL): |
| FL = -5.02 + 0.392(GA) |
| R2 = 0.8215 |
| Lens diameter (LD): |
| LD = 2.205 - 0.518(GA) + 0.0401(GA)2 - 0.000856(GA)3 |
| R2 = 0.9618 |
| Body weight (BW): |
| BW = 0.5488 - 0.01714(GA) - 0.01180(GA)2 + 0.0008279(GA)3 |
| R2 = 0.9906 |
| Placental diameter (PD): |
| PD = -11.96 + 2.09(GA) - 0.046(GA)2 - 0.0005(GA)3 |
| R2 = 0.8941 |
| Placental thickness (PT): |
| PT = 4.10 - 1.14(GA) + 0.115(GA)2 - 0.0031(GA)3 |
| R2 = 0.7562 |
| Placental weight (PW): |
| PW = -0.54180 + 0.07887(GA) - 0.002243(GA)2 |
| R2 = 0.8237 |
GA, gestational age