Research Article

Evaluating the Agreement of Risk Categorization for Fetal Down Syndrome Screening between Ultrasound-Based Gestational Age and Menstrual-Based Gestational Age by Maternal Serum Markers

Table 3

The number of different days between LMP-based GA and US-based GA in gestational age estimation for those excluded due to trimester discrepancy.

Mean different daysFirst trimesterSecond trimesterTotal
N%N%N%

1–3677.1205.4876.6
4–716817.96918.623718
8–1425126.78322.433425.4
15–2115416.4371019114.5
22–2810611.34411.915011.4
>2819420.611731.631123.7
Total9401003701001310100