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. Author manuscript; available in PMC: 2015 Jun 26.
Published in final edited form as: Prenat Diagn. 2013 Dec 17;34(3):214–222. doi: 10.1002/pd.4282

Table.

Maternal and infant characteristics associated with maternal report of prenatal CHD diagnosis, National Birth Defects Prevention Study, 1998-2005 (n=7,299)

Report of prenatal diagnosis
Characteristic N n(%) cPR (95% CI) aPR (95% CI)
CHD Complexity
    Simple (one heart defect) 5404 685 (12.7%) Reference Reference
    Two or more associated or complex heart defects 1895 412 (21.7%) 1.72 (1.54,1.92) 1.61 (1.44,1.81)
Presence of Extracardiac Defects
    No (isolated; no extracardiac defects) 6104 812 (13.3%) Reference Reference
    Yes (extracardiac defects present) 1195 285 (23.8%) 1.79 (1.59,2.02) 1.65 (1.46,1.87)
Year of Due Date
    1998 659 84 (12.7%) 0.78 (0.61,0.99) 0.79 (0.62,1.01)
    1999 782 114 (14.6%) 0.89 (0.72,1.11) 0.88 (0.71,1.10)
    2000 851 126 (14.8%) 0.91 (0.74,1.12) 0.90 (0.73,1.12)
    2001 880 126 (14.3%) 0.88 (0.71,1.08) 0.86 (0.70,1.07)
    2002 813 139 (17.1%) 1.05 (0.86,1.28) 0.95 (0.77,1.16)
    2003 959 146 (15.2%) 0.93 (0.76,1.14) 0.91 (0.74,1.11)
    2004 1246 181 (14.5%) 0.89 (0.74,1.08) 0.90 (0.74,1.09)
    2005 1109 181 (16.3%) Reference Reference
Family History of CHD (first degree relative)
    No 7047 1038 (14.7%) Reference Reference
    Yes 252 59 (23.4%) 1.59 (1.26,2.00) 1.47 (1.16,1.86)
Gestational Age
    Very preterm (<32 completed weeks) 613 84 (13.7%) 0.93 (0.76,1.15) 0.97 (0.78,1.20)
    Preterm (32-36 completed weeks) 1309 224 (17.1%) 1.17 (1.02,1.34) 1.09 (0.94,1.25)
    Term (≥ 37 completed weeks) 5376 789 (14.7%) Reference Reference
    Unknown/missing 1 0 (0%) NC NC
Plurality
    Singleton 6765 989 (14.6%) Reference Reference
    Twins or higher order gestation 525 106 (20.2%) 1.38 (1.15,1.65) 1.26 (1.03,1.54)
    Unknown/missing 9 2 (22.2%) NC NC
Maternal Race/Ethnicity
    Non-Hispanic white 4300 745 (17.3%) Reference Reference
    Non-Hispanic black 823 109 (13.2%) 0.76 (0.63,0.92) 0.83 (0.68,1.02)
    Hispanic 1741 166 (9.5%) 0.55 (0.47,0.65) 0.72 (0.59,0.89)
    Other 434 76 (17.5%) 1.01 (0.82,1.25) 0.97 (0.78,1.20)
    Unknown/missing 1 1 (100.0%) NC NC
Maternal Age (at delivery)
    <30 years 4336 542 (12.5%) Reference Reference
    >=30 years 2963 555 (18.7%) 1.50 (1.34,1.67) 1.13 (1.00,1.28)
Maternal Level of Education
    0-12 years 3169 376 (11.9%) Reference Reference
    >12 years 4040 709 (17.5%) 1.48 (1.32,1.66) 1.14 (1.00,1.30)
    Unknown/missing 90 12 (13.3%) NC NC
Prepregnancy Maternal Body Mass Index (BMI)
    Underweight (<18.5 kg/m2) 384 60 (15.6%) 0.92 (0.72,1.17) 1.00 (0.79,1.28)
    Normal weight (18.5-24 kg/m2) 3492 596 (17.1%) Reference Reference
    Overweight (25-29 kg/m2) 1643 231 (14.1%) 0.82 (0.72,0.95) 0.87 (0.76,1.00)
    Obese (>=30 kg/m2) 1478 183 (12.4%) 0.73 (0.62,0.85) 0.78 (0.66,0.92)
    Unknown/missing 302 27 (8.9%) NC NC
Pregestational Diabetes
    None 6994 1016 (14.5%) Reference Reference
    Type 1 108 26 (24.1%) 1.66 (1.18,2.33) 1.57 (1.10,2.24)
    Type 2 138 41 (29.7%) 2.05 (1.57,2.66) 2.46 (1.86,3.24)
    Unknown/missing 59 14 (23.7%) NC NC
Hypertension (before or during index pregnancy)
    No 6100 951 (15.6%) Reference Reference
    Yes 1193 145 (12.2%) 0.78 (0.66,0.92) 0.81 (0.68,0.97)
    Unknown/missing 6 1 (16.7%) NC NC
Maternal Fertility Treatments
    No 6801 1002 (14.7%) Reference Reference
    Yes 426 84 (19.7%) 1.34 (1.10,1.63) 0.86 (0.68,1.08)
    Unknown/missing 72 11 (15.3%) NC NC
Number of Pregnancy Losses before this Pregnancy
    None 4681 679 (14.5%) Reference Reference
    One 1670 269 (16.1%) 1.11 (0.98,1.26) 1.05 (0.92,1.20)
    Two 606 84 (13.9%) 0.96 (0.77,1.18) 0.87 (0.70,1.07)
    More than two 338 65 (19.2%) 1.33 (1.05,1.67) 1.15 (0.90,1.45)
    Unknown/missing 4 0 (0.0%) NC NC
Pregnancy Intention
    Intended 4191 668 (15.9%) Reference Reference
    Mistimed/ambivalent 1700 247 (14.5%) 0.91 (0.80,1.04) 1.10 (0.95,1.27)
    Unwanted 1379 178 (12.9%) 0.81 (0.69,0.94) 0.96 (0.82,1.13)
    Unknown/missing 29 4 (13.8%) NC NC
Trimester of First Prenatal Care Visit
    1st 6121 947 (15.5%) Reference Reference
    2nd 895 117 (13.1%) 0.84 (0.71,1.01) 0.98 (0.82,1.18)
    3rd 66 7 (10.6%) 0.69 (0.34,1.38) 0.78 (0.41,1.47)
    Unknown/missing 217 26 (12.0%) NC NC
Time to Interview
    6 weeks-6 months 1652 341 (20.6%) Reference Reference
    7-12 months 3132 477 (15.2%) 0.74 (0.65,0.84) 0.77 (0.67,0.88)
    13-18 months 1663 209 (12.6%) 0.61 (0.52,0.71) 0.71 (0.60,0.84)
    19-24 months 766 62 (8.1%) 0.39 (0.30,.51) 0.51 (0.39,0.68)
    Unknown/missing 86 8 (9.3%) NC NC
Study Site
    A 1188 84 (7.1%) Reference Reference
    B 1199 86 (7.2%) 1.01 (0.76,1.36) 1.19 (0.86,1.64)
    C 855 112 (13.1%) 1.85 (1.42,2.42) 1.96 (1.46,2.64)
    D 741 113 (15.2%) 2.16 (1.65,2.82) 2.18 (1.65,2.87)
    E 285 45 (15.8%) 2.23 (1.59,3.13) 2.16 (1.51,3.11)
    F 483 77 (15.9%) 2.25 (1.69,3.01) 2.13 (1.56,2.90)
    G 944 188 (19.9%) 2.82 (2.21,3.59) 2.64 (2.05,3.41)
    H 548 122 (22.3%) 3.15 (2.43,4.08) 2.71 (2.07,3.55)
    I 1056 270 (25.6%) 3.62 (2.87,4.55) 3.09 (2.42,3.94)

Bold indicates significance at < 0.05 level

CHD=congenital heart defect

NBDPS=National Birth Defects Prevention Study

cPR=crude prevalence ratio estimated from a Poisson regression model with robust error variance

aPR=adjusted prevalence ratio estimated from a Poisson regression model with robust error variance

CI=confidence interval

NC=not calculated

a Adjusted for all variables listed; excludes cases with at least one missing response

b A case was categorized as having a “simple” heart defect if s/he had one heart defect or a well-defined constellation of defects such as hypoplastic left heart syndrome or tetralogy of Fallot

c The study catchment area changed over time