Table 4.

Umbilical artery resistance index centile (RI) values according to gestational age

Gestational age (weeks + days)	Centile
	3rd	5th	10th	50th	90th	95th	97th
24+0	0.58	0.60	0.62	0.69	0.76	0.78	0.79
25+0	0.57	0.58	0.61	0.68	0.75	0.77	0.79
26+0	0.56	0.57	0.60	0.67	0.75	0.77	0.78
27+0	0.55	0.56	0.59	0.67	0.74	0.76	0.78
28+0	0.54	0.55	0.58	0.66	0.74	0.76	0.77
29+0	0.53	0.55	0.57	0.65	0.73	0.75	0.77
30+0	0.52	0.54	0.56	0.64	0.72	0.75	0.76
31+0	0.51	0.53	0.55	0.63	0.72	0.74	0.75
32+0	0.50	0.52	0.54	0.63	0.71	0.73	0.74
33+0	0.49	0.51	0.53	0.62	0.70	0.72	0.74
34+0	0.49	0.50	0.52	0.61	0.69	0.71	0.73
35+0	0.48	0.49	0.52	0.60	0.68	0.70	0.72
36+0	0.47	0.48	0.51	0.59	0.67	0.69	0.71
37+0	0.46	0.47	0.50	0.58	0.66	0.68	0.70
38+0	0.45	0.46	0.49	0.57	0.65	0.67	0.69
39+0	0.44	0.45	0.48	0.56	0.64	0.66	0.68
40+0	0.43	0.44	0.46	0.55	0.63	0.65	0.66

Drukker et al. International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21^st Project. Am J Obstet Gynecol 2020.