Measurements for Amniotic Fluid Assessment

TABLE C-1

Amniotic Fluid Index Values in Normal Pregnancy

Gestational age (wk)	AMNIOTIC FLUID INDEX (mm) BY PERCENTILE
Gestational age (wk)	3rd	5th	50th	95th	97th
16	73	79	121	185	201
17	77	83	127	194	211
18	80	87	133	202	220
19	83	90	137	207	225
20	86	93	141	212	230
21	88	95	143	214	233
22	89	97	145	216	235
23	90	98	146	218	237
24	90	98	147	219	238
25	89	97	147	221	240
26	89	97	147	223	242
27	85	95	146	226	245
28	86	94	146	228	249
29	84	92	145	231	254
30	82	90	145	234	258
31	79	88	144	238	263
32	77	86	144	242	269
33	74	83	143	245	274
34	72	81	142	248	278
35	70	79	140	249	279
36	68	77	138	249	279
37	66	75	135	244	275
38	65	73	132	239	269
39	64	72	127	226	255
40	63	71	123	214	240
41	63	70	116	194	216
42	63	69	110	175	192

Adapted from Moore TR, Cayle JE: The amniotic fluid index in normal human pregnancy. Am J Obstet Gynecol 162:1168, 1990.

TABLE C-2

Amniotic Fluid Index Values in Normal Pregnancy

Menstrual Age (wk)	AMNIOTIC FLUID INDEX (cm) BY PERCENTILE
Menstrual Age (wk)	5th	10th	50th	Mean	90th	95th
14	2.8	3.1	5.0	5.4	8.0	8.6
15	3.2	3.6	5.4	5.7	8.2	9.1
16	3.6	4.1	5.8	6.1	8.5	9.6
17	4.1	4.0	6.3	6.6	9.0	10.3
18	4.6	5.1	6.8	7.1	9.7	11.1
19	5.1	5.6	7.4	7.7	10.4	12.0
20	5.5	6.1	8.0	8.3	11.3	12.9
21	5.9	6.6	8.7	8.9	12.2	13.9
22	6.3	7.1	9.3	9.6	13.2	14.9
23	6.7	7.5	10.0	10.3	14.2	15.9
24	7.0	7.9	10.7	11.0	15.2	16.9
25	7.3	8.2	11.4	11.7	16.1	17.8
26	7.5	8.4	12.0	12.3	17.0	18.7
27	7.6	8.6	12.6	12.8	17.8	19.4
28	7.6	8.6	13.0	13.3	18.4	19.9
29	7.6	8.6	13.4	13.6	18.8	20.4
30	7.5	8.5	13.6	13.8	18.9	20.6
31	7.3	8.4	13.6	13.8	18.9	20.6
32	7.1	8.1	13.6	13.7	18.7	20.4
33	6.8	7.8	13.3	13.4	18.2	20.0
34	6.4	7.4	13.9	13.0	17.7	19.4
35	6.0	7.0	12.4	12.5	16.9	18.7
36	5.6	6.5	11.8	11.8	16.2	17.9
37	5.1	6.0	11.1	11.1	15.3	16.9
38	4.7	5.5	10.3	10.3	14.4	15.9
39	4.2	5.0	9.4	9.4	13.7	14.9
40	3.7	4.5	8.6	8.6	12.9	13.9
41	3.3	4.0	7.8	7.7	12.3	12.9