Fetal Doppler Assessment (Noncardiac)

TABLE D-1

Resistance Index of the Uterine Artery

Gestation (wk)	5th Percentile	50th Percentile	95th Percentile
18	0.222	0.447	0.659
19	0.204	0.429	0.641
20	0.194	0.419	0.630
21	0.186	0.411	0.622
22	0.180	0.405	0.615
23	0.175	0.400	0.610
24	0.171	0.395	0.605
25	0.167	0.391	0.601
26	0.163	0.387	0.597
27	0.160	0.384	0.593
28	0.157	0.380	0.590
29	0.154	0.378	0.587
30	0.152	0.375	0.584
31	0.150	0.372	0.581
32	0.147	0.370	0.578
33	0.145	0.368	0.576
34	0.144	0.366	0.574
35	0.142	0.364	0.571
36	0.140	0.362	0.569
37	0.139	0.360	0.567
38	0.137	0.358	0.566
39	0.136	0.357	0.564
40	0.135	0.355	0.562

From Merz E (ed): Ultrasonography in Obstetrics and Gynecology. Stuttgart, Thieme, 2005, pp 469-480, 613, 614.

TABLE D-2

Pulsatility Index of the Uterine Artery

Gestation (wk)	5th Percentile	50th Percentile	95th Percentile
18	0.509	0.888	1.407
19	0.460	0.838	1.356
20	0.436	0.812	1.328
21	0.420	0.795	1.309
22	0.407	0.781	1.293
23	0.397	0.769	1.280
24	0.388	0.759	1.268
25	0.381	0.751	1.258
26	0.374	0.743	1.248
27	0.369	0.736	1.239
28	0.363	0.729	1.230
29	0.358	0.722	1.222
30	0.354	0.716	1.214
31	0.349	0.711	1.207
32	0.345	0.705	1.199
33	0.341	0.700	1.192
34	0.337	0.695	1.185
35	0.333	0.690	1.178
36	0.330	0.684	1.171
37	0.326	0.679	1.164
38	0.322	0.674	1.157
39	0.318	0.669	1.150
40	0.313	0.663	1.143

From Merz E (ed): Ultrasonography in Obstetrics and Gynecology. Stuttgart, Thieme, 2005, pp 469-480, 613, 614.

TABLE D-3

Reference Values for Serial Measurements of the Umbilical Artery Systolic/Diastolic Ratio

Gestational age (wk)	UMBILICAL ARTERY SYSTOLIC/DIASTOLIC RATIO BY PERCENTILE
Gestational age (wk)	2.5th	5th	10th	25th	50th	75th	90th	95th	97.5th
19	2.73	2.93	3.19	3.67	4.28	5.00	5.75	6.26	6.73
20	2.63	2.83	3.07	3.53	4.11	4.80	5.51	5.99	4.43
21	2.51	2.70	2.93	3.36	3.91	4.55	5.22	5.67	6.09
22	2.43	2.60	2.83	3.24	3.77	4.38	5.03	5.45	5.85
23	2.34	2.51	2.72	3.11	3.62	4.21	4.82	5.22	5.61
24	2.25	2.41	2.62	2.99	3.48	4.04	4.63	5.02	5.38
25	2.17	2.33	2.52	2.88	3.35	3.89	4.45	4.83	5.18
26	2.09	2.24	2.43	2.78	3.23	3.75	4.30	4.66	5.00
27	2.02	2.17	2.35	2.69	3.12	3.63	4.15	4.50	4.83
28	1.95	2.09	2.27	2.60	3.02	3.51	4.02	4.36	4.67
29	1.89	2.03	2.20	2.52	2.92	3.40	3.89	4.22	4.53
30	1.83	1.96	2.13	2.44	2.83	3.30	3.78	4.10	4.40
31	1.77	1.90	2.06	2.36	2.75	3.20	3.67	3.98	4.27
32	1.71	1.84	2.00	2.29	2.67	3.11	3.57	3.87	4.16
33	1.66	1.79	1.94	2.23	2.60	3.03	3.48	3.77	4.06
34	1.61	1.73	1.88	2.16	2.53	2.95	3.39	3.68	3.96
35	1.57	1.68	1.83	2.11	2.46	2.87	3.30	3.59	3.86
36	1.52	1.64	1.78	2.05	2.40	2.80	3.23	3.51	3.78
37	1.48	1.59	1.73	2.00	2.34	2.74	3.15	3.43	3.69
38	1.44	1.55	1.69	1.95	2.28	2.67	3.08	3.36	3.62
39	1.40	1.51	1.64	1.90	2.23	2.61	3.02	3.29	3.54
40	1.36	1.47	1.60	1.85	2.18	2.56	1.96	3.22	3.48
41	1.33	1.43	1.56	1.81	2.13	2.50	2.90	3.16	3.41

From Acharya G, Wilsgaard T, Bernsten GKR, et al: Reference ranges for serial measurements of umbilical artery Doppler indices in the second half of pregnancy. Am J Obstet Gynecol 192:937, 2005.

TABLE D-4

Resistance Index of the Umbilical Artery Between 20 and 40 Weeks of Gestation

Gestation (wk)	5th Percentile	50th Percentile	95th Percentile
20	0.567	0.690	0.802
21	0.557	0.680	0.793
22	0.548	0.671	0.784
23	0.539	0.663	0.776
24	0.530	0.655	0.768
25	0.522	0.646	0.760
26	0.514	0.639	0.752
27	0.506	0.631	0.745
28	0.498	0.623	0.737
29	0.490	0.615	0.730
30	0.482	0.608	0.723
31	0.474	0.600	0.715
32	0.465	0.592	0.707
33	0.457	0.584	0.700
34	0.449	0.576	0.692
35	0.440	0.567	0.684
36	0.431	0.559	0.675
37	0.422	0.550	0.667
38	0.412	0.540	0.657
39	0.402	0.530	0.648
40	0.390	0.519	0.637