Table 2

Occupational groups of mothers with jobs during the critical period who participated in the National Birth Defects Prevention Study, 1997–2003*

Occupational groupCases (n = 8977)n (%)†Controls (n = 3383)n (%)†
Math and computer scientists162 (1.80)‡59 (1.74)‡
Scientists172 (1.92)‡60 (1.77)‡
    Surveyors, geologists, geoscientists0 (0.00)4 (6.67)
    Engineers, science technicians36 (20.93)8 (13.33)
    Biological scientists94 (54.65)37 (61.67)
    Chemical scientists and pharmacists42 (24.42)11 (18.33)
Artists54 (0.60)‡14 (0.41)‡
    Artists9 (16.67)4 (26.67)
    Photographers, photo processors24 (44.44)5 (33.33)
    Printers21 (38.89)5 (33.33)
Healthcare workers1093 (12.18)‡441 (13.04)‡
    Health care practitioners58 (5.31)30 (6.80)
    Dentists, dental assistants64 (5.86)33 (7.48)
    Nurses, therapists, health technicians972 (88.93)378 (85.71)
Public servants63 (0.70)‡26 (0.77)‡
    Police, guards54 (85.71)20 (76.92)
    Firefighters0 (0.00)1 (3.85)
    Armed forces9 (14.29)5 (19.23)
Food servers/processors1124 (12.52)‡411 (12.15)‡
    Food service workers999 (88.88)364 (88.56)
    Food processing workers133 (11.83)49 (11.92)
Janitors, cleaners350 (3.90)‡104 (3.07)‡
Personal service, athletes420 (4.68)‡164 (4.85)‡
    Entertainers, athletes67 (15.95)34 (20.73)
    Personal service workers354 (84.29)130 (79.27)
Hairdressers and cosmetologists143 (1.59)‡45 (1.33)‡
Office other954 (10.63)‡353 (10.43)‡
    Business and financial specialists449 (47.06)159 (45.04)
    Architects, drafters, designers75 (7.86)21 (5.95)
    Legal and social service workers335 (35.12)132 (37.39)
    Media and communication workers61 (6.39)22 (6.23)
    Messengers39 (4.09)19 (5.38)
Managers, administrators713 (7.94)‡302 (8.93)‡
Teachers720 (8.02)‡342 (10.11)‡
Sales workers1183 (13.18)‡436 (12.89)‡
Administrative support2001 (22.29)‡735 (21.73)‡
Farm workers175 (1.95)‡57 (1.68)‡
Landscapers23 (0.26)‡3 (0.09)‡
    Landscapers, groundskeepers10 (43.48)0 (0.00)
    Forestry and logging workers3 (13.04)0 (0.00)
    Sawmill workers10 (43.48)3 (100.00)
Construction workers100 (1.11)‡33 (0.98)‡
    Construction workers8 (8.00)5 (15.15)
    Carpenters, wood workers14 (14.00)6 (18.18)
    Electricians, electrical and electronics workers61 (61.00)16 (48.48)
    Stone, glass and concrete workers4 (4.00)3 (9.09)
    Painters14 (14.00)3 (9.09)
Metal workers/welders29 (0.32)‡5 (0.15)‡
    Foundry and smelter workers3 (10.34)0 (0.00)
    Sheet metal, iron and other metal workers22 (75.86)2 (40.00)
    Welders, cutters4 (13.79)3 (60.00)
Dry cleaners45 (0.50)‡10 (0.30)‡
Chemical/semiconductor workers76 (0.85)‡17 (0.50)‡
    Chemical workers, NEC73 (96.05)14 (82.35)
    Semiconductor processors3 (3.95)3 (17.65)
Textile, paper workers77 (0.86)‡30 (0.89)‡
    Textile workers66 (85.71)25 (83.33)
    Paper workers12 (15.58)5 (16.67)
Shippers, operators175 (1.95)‡78 (2.31)‡
    Shippers163 (93.14)69 (88.46)
    Plant and system operators6 (3.43)3 (3.85)
    Material moving equipment operators6 (3.43)6 (7.69)
Electronic equipment operators107 (1.19)‡36 (1.06)‡
Manufacturing, transportation workers120 (1.34)‡43 (1.27)‡
    Vehicle manufacturing20 (16.67)6 (13.95)
    Vehicle mechanics3 (2.50)2 (4.65)
    Mechanics, NEC19 (15.83)6 (13.95)
    Motor vehicle operators55 (45.83)21 (48.84)
    Aircraft operators, air crew16 (13.33)7 (16.28)
    Rail transportation workers3 (2.50)0 (0.00)
    Water transportation workers1 (0.83)1 (2.33)
    Transportation workers, NEC2 (1.67)0 (0.00)
    Service station attendants2 (1.67)0 (0.00)
  • NEC, not elsewhere classified.

  • *The critical period is defined as 1 month prior to conception through the end of the third month of pregnancy.

  • †Percentages may not add to 100% because of multiple jobs in some instances. Percentage of main occupations (n = 24) is of total cases or controls and percentage for each subgroup is of the parent group.

  • ‡Percentage of total cases or controls.