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. Author manuscript; available in PMC: 2022 Apr 18.
Published in final edited form as: Am J Intellect Dev Disabil. 2018 Sep;123(5):399–411. doi: 10.1352/1944-7558-123.5.399

Table 2.

Characteristics of Study Population, 2002–2009 Massachusetts Pregnancy to Early Life Longitudinal Data System

Characteristics IDD
n = 498
n (%)
No IDD
n = 1,531
n (%)
Test statistic χ2 p-value
Age 0.45 0.930
 < 20 75 (15.1) 225 (14.7
 20–29 256 (51.4) 810 (52.9)
 30–39 149 (29.9) 438 (28.6)
 40+ 18 (3.6) 58 (3.8)
Education 100.54 <0.001
 Less than high school 147 (29.6) 293 (19.2)
 High school graduate 230 (46.3) 474 (31.0)
 Some or more college 120 (24.1) 761 (49.8)
Maternal race/ethnicity 14.65 0.002
 Hispanic 99 (19.9) 318 (20.8)
 Non-Hispanic White 317 (63.7) 942 (61.5)
 Non-Hispanic Black 71 (14.3) 175 (11.4)
 Other 11 (2.2) 96 (6.3)
Marital Status (% married) 151 (30.3) 792 (51.9) 70.06 <0.001
Public health insurance 388 (78.7) 708 (46.5) 155.49 <0.001
Other Characteristics
Father named on birth certificate 337 (67.7) 1,334 (87.1) 97.95 <0.001
Smoking during pregnancy 92 (18.6) 145 (9.5) 29.78 <0.001
Prenatal care 1st trimester 332 (67.6) 1,138 (74.9) 9.92 0.002
Prenatal care utilization index 27.56 <0.001
 Inadequate 92 (18.7) 168 (11.1)
 Intermediate 34 (6.9) 120 (7.9)
 Adequate 162 (32.9) 652 (43.0)
 Adequate plus 204 (41.5) 577 (38.0)
Pregnancy complications
 Diabetes 25 (5.8) 56 (3.7) 1.89 0.170
 Hypertension 25 (5.8) 46 (3.0) 4.62 0.032
 Other pregnancy complication 342 (70.4) 742 (48.9) 68.26 <0.001
Mental illness
 Major Mental illness 129 (25.9) 59 (3.9) 217.32 <0.001
 Other mental illness 105 (37.2) 80 (5.2) 337.25 <0.001

Note. IDD = intellectual and developmental disabilities.