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 4

Down syndrome screening results and frequency of high/low-risk categorization according to the type of screening.

	High risk, n (%)	Low risk, n (%)
US-based screening
(i) Total	927 (11.5%)	7144 (88.5%)
(a) First trimester	340 (8.4%)	3715 (91.6%)
(b) Second trimester	587 (14.6%)	3429 (85.4%)
(ii) Down syndrome detected	15/927	5/7144
LMP-based screening
(i) Total	1293 (16.0%)	6778 (84.0%)
(a) First trimester	468 (11.5%)	3587 (88.5%)
(b) Second trimester	825 (20.5%)	3191 (79.5%)
(ii) Down syndrome detected	14/1293	6/6778