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 2 Gestational Age-Specific Numbers and Rates of Perinatal Death among Female 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	614	5,838	184	123.7	3,665,497	0.22
29	530	7,000	158	91.4	3,659,045	0.19
30	611	9,742	179	76.3	3,651,515	0.22
31	578	12,493	173	57.5	3,641,162	0.21
32	632	17,168	195	46.5	3,628,091	0.23
33	654	25,282	187	32.4	3,610,291	0.23
34	747	44,275	221	21.5	3,584,355	0.27
35	796	75,238	234	13.5	3,539,333	0.29
36	874	133,386	286	8.6	3,463,299	0.33
37	927	267,501	337	4.7	3,329,039	0.38
38	1,071	563,676	361	2.5	3,060,611	0.47
39	1,072	885,523	419	1.7	2,495,864	0.60
40	926	851,848	376	1.5	1,609,269	0.81
41	505	455,313	222	1.6	756,495	0.96
≥42*	443	300,234	198	2.1	300,677	2.13
Total‡	15,537	3,707,616	6,614	6.0	3,723,153	5.95

† 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.

ISSN: 1471-2393