Customized birth weight for gestational age standards: Perinatal mortality patterns are consistent with separate standards for males and females but not for blacks and whites

Table 1 Gestational Age-Specific Numbers and Rates of Perinatal Death among Male Singleton Births, United States, 1997 and 1998.

Gestational age	Stillbirths	Live births	Early neonatal deaths	Perinatal mortality rate (1)†	Fetuses at risk	Perinatal mortality rate (2)†
28	648	6,808	263	122.2	3,841,944	0.24
29	579	8,100	221	92.2	3,834,488	0.21
30	701	11,297	230	77.6	3,825,809	0.24
31	668	14,339	208	58.4	3,813,811	0.23
32	809	20,242	209	48.4	3,798,804	0.27
33	786	30,140	212	32.3	3,777,753	0.26
34	881	51,673	298	22.4	3,746,827	0.31
35	915	86,166	338	14.4	3,694,273	0.34
36	1,033	154,986	354	8.9	3,607,192	0.38
37	1,144	308,629	394	5.0	3,451,173	0.45
38	1,173	626,450	470	2.6	3,141,400	0.52
39	1,122	925,764	541	1.8	2,513,777	0.66
40	897	848,527	431	1.6	1,586,891	0.84
41	469	444,468	237	1.6	737,467	0.96
≥42*	454	292,076	229	2.3	292,530	2.33
Total‡	17,680	3,888,014	8,800	6.8	3,905,694	6.78

† Total births at each gestational week served as the denominator for perinatal mortality rates (1), while perinatal mortality rates (2) were calculated using fetuses at risk as the denominator (see text). All rates are expressed per 1,000.
* Large increase in perinatal mortality (2) at ≥42 weeks is partly because the period of risk exceeds 1 week (see also Figures 3-5).
‡ All gestational ages, including those ≥22 weeks and those with missing gestational age.

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