Table 5. AUC-ROC scores for SPTB with increasing gestational age of sample collection.

Gest. age range at sample collection	4–5 weeks	6–9 weeks	9–13 weeks	Subgroup of interest: 8–11 weeks (NIPT time frame)
#samples	14	13	14	13
Mean gest. age at sample collection (± SD)	4.9±0.7 weeks	7.9±1.1 weeks	11.2±1.7 weeks	9.4±1.0 weeks
AUC-ROC	1	0.95	0.88	0.94
AUROC-ROC 95% Confidence Interval	0.77–1.00	0.68–1.00	0.60–0.99	0.67–1.00
Preterm	8	3	3	4
Full-term	6	10	11	9
Sensitivity	100	100	100	100
Specificity	100	80	64	78
P value	P<0.0001	P<0.0001	P = 0.0002	P<0.0001