Table 1

Numbers of births with missing data, by type of data.

Type of missing data

Births (%) missing

Maternal age

296 (0.1%)

Maternal race

9966 (2.9%)

Maternal education

35670 (10.3%)

Any maternal key data

48307 (13.9%)

Paternal age

29997 (8.6%)

Paternal race

39772 (11.5%)

Paternal education

73421 (21.15%)

Any paternal key data

77737 (22.4%)

Any key data

82297 (23.7%)

Numbers of births with missing data, by type of data. Note, some births had more than one type of missing data. "Key data" includes age, race and educational attainment.

Nicolaidis et al. BMC Pregnancy and Childbirth 2004 4:10   doi:10.1186/1471-2393-4-10