question: Compared to Crown-rump length method what was the result of Last menstrual period method on Gestational age at the ultrasound visit ?
context: Mean (SD) gestational age at the ultrasound visit was 76.1 (12.5) days [10.9 (1.8) weeks] by LMP and 73.3 (12.9) days [10.5 (1.8) weeks] by CRL (p < 0.001), with a mean (SD) difference of 2.8 (10.8) days