Table 1. Characteristics of mothers and their infants who were and who were not exposed to a major radiodiagnostic testing in pregnancy.
| Characteristica | Major Radiodiagnostic Test in Pregnancy | |
| Exposed (n = 5,590) | Unexposed (n = 1,829,927) | |
| Maternal | ||
| Mean (SD) age at delivery, y | 29.0 (5.7) | 29.3 (5.4) |
| Age at delivery, y | ||
| 16–19 | 168 (3.0) | 47,729 (2.6) |
| 20–24 | 1,013 (18.1) | 273,835 (15.0) |
| 25–29 | 1,667 (29.8) | 558,566 (30.5) |
| 30–34 | 1,662 (29.7) | 607,798 (33.2) |
| 35–39 | 784 (14.0) | 265,545 (14.5) |
| 40–44 | 170 (3.0) | 43,674 (2.4) |
| 45–50 | 8 (0.14) | 1,464 (0.080) |
| Income quintile (Q) | ||
| Q1 (lowest) | 1,435 (25.7) | 416,705 (22.8) |
| Q5 (highest) | 784 (14.0) | 302,374 (16.5) |
| Urban residence | 4,737 (84.7) | 1,528,253 (83.5) |
| Mean (SD) length of stay at delivery hospitalization, d | 2.5 (2.2) | 2.3 (1.6) |
| Cancer diagnosis in pregnancy or ≤6 mo after delivery | 35 (0.63) | 1,004 (0.050) |
| Prenatal ultrasonography any time in pregnancy | 4,956 (88.7) | 1,452,376 (79.4) |
| Prenatal ultrasonography <16 wk gestation | 1,845 (33.0) | 348,104 (19.0) |
| Major radiodiagnostic testing in pregnancy | ||
| Estimated mean (SD) gestational age at exposure, wk | 15.7 (12.8) | — |
| Estimated gestational age at exposure, wk | ||
| 0–14 | 2,866 (51.3) | — |
| ≥15 | 2,724 (48.7) | — |
| Mean (SD) number of major radiodiagnostic tests | 1.20 (0.59) | — |
| Number of major radiodiagnostic tests | ||
| 1 | 4,756 (85.1) | — |
| ≥2 | 834 (14.9) | — |
| Major radiodiagnostic test type | — | |
| Radionuclide testb | 1,527 (27.3) | |
| CT scan | 4,088 (73.1) | — |
| Anatomical location of the CT scan | — | |
| Extremity or head | 2,762 (67.6) | — |
| Thorax | 405 (9.9) | — |
| Abdomen or spine | 448 (11.0) | — |
| Pelvis | 473 (11.6) | — |
| Liveborn infant | ||
| Female sex | 2,745 (49.1) | 891,969 (48.7) |
| Mean (SD) gestational age at birth, wkc | 39.1 (1.2) | 39.3 (1.1) |
| Mean (SD) birthweight, g | 3,476 (466) | 3,497 (462) |
| Any chromosomal anomaly | 7 (0.13) | 2,013 (0.11) |
| Any congenital anomaly | 220 (3.9) | 67,284 (3.7) |
| Any major radiodiagnostic test exposure after birth | 244 (4.4) | 80,348 (4.4) |
a
All data are presented as a number (%) unless otherwise indicated.
b
Ventilation-perfusion lung scan (89.4%) or thyroid scan (10.6%).
c
Determined using data from April 1, 2002 onward.