Table 9.

Fetal heart rate (female), beats per minute

Gestation (week)	2.5th percentile	5th percentile	10th percentile	25th percentile	Mean	75th percentile	90th percentile	95th percentile	97.5th percentile
20	131	134	137	142	147	153	158	161	164
21	131	133	136	141	146	152	157	160	163
22	130	132	135	140	146	151	156	159	162
23	129	132	134	139	145	151	156	159	161
24	128	131	134	139	144	150	155	158	161
25	127	130	133	138	144	150	155	158	161
26	127	129	132	138	143	149	154	157	160
27	126	129	132	137	143	149	154	157	160
28	125	128	131	136	142	148	154	157	160
29	125	127	131	136	142	148	153	156	159
30	124	127	130	135	141	147	153	156	159
31	124	126	130	135	141	147	153	156	159
32	123	126	129	135	141	147	152	156	159
33	123	125	129	134	140	147	152	156	159
34	122	125	128	134	140	146	152	156	159
35	122	124	128	133	140	146	152	155	158
36	121	124	127	133	139	146	152	155	158
37	121	124	127	133	139	146	152	155	158
38	120	123	127	132	139	145	151	155	158
39	120	123	126	132	139	145	151	155	158
40	120	123	126	132	138	145	151	155	158

Sex-specific reference values of the fetal heart rate (HR) for the 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97.5th percentiles during the second half of pregnancy (female fetuses)