Table 2.

Characteristics of Study Population, California 1987–1994

Live Births
(n = 4 590 333)
MR of Unknown Cause
(n = 11 114)
n*(%)n*(%)
Child sex
 Male2 350 287(51.2)7027(63.2)
 Female2 240 020(48.8)4087(36.8)
Birth weight
 <2500 g274 419(6.0)2574(23.2)
 ≥2500 g4 314 859(94.0)8537(76.8)
Plurality
 Singleton4 489 348(97.8)10 520(94.7)
 Multiple100 910(2.2)594(5.3)
Birth order
 11 824 165(39.7)3685(33.2)
 21 412 612(30.8)3258(29.3)
 ≥31 347 012(29.3)4148(37.3)
Maternal age
 <20533 319(11.6)1335(12.0)
 20–241 188 530(25.9)2833(25.5)
 25–291 352 240(29.5)3064(27.6)
 30–341 009 809(22.0)2462(22.2)
 ≥35504 751(11.0)1420(12.8)
Maternal race/ethnicity
 White1 884 556(41.1)4189(37.7)
 Hispanic1 845 765(40.2)4239(38.1)
 Black367 611(8.0)1650(14.8)
 Asian267 685(5.8)518(4.7)
 Other198 052(4.3)459(4.1)
Maternal birth place
 California1 812 955(39.5)5077(45.7)
 Other United States883 320(19.2)2042(18.4)
 Mexico1 088 144(23.7)2324(20.9)
 China40 365(0.9)50(0.4)
 Japan16 793(0.4)31(0.3)
 Vietnam62 255(1.4)129(1.2)
 Philippines95 031(2.1)202(1.8)
 Other591 470(12.9)1259(11.3)
Maternal education
 <High school1 209 943(34.1)3322(40.2)
 High school graduate1 074 594(30.3)2686(32.5)
 College990 677(27.9)1846(22.3)
 Postgraduate245 721(6.9)326(3.9)
  • * Numbers may not add up to column total because of records with missing data.