Characteristics of the study sample, overall and by tertile of neighbourhood crime rate (n=34 383 births, Chicago, Illinois, USA, 2009–2013)*
| Overall | Total neighbourhood crime rate | |||
| Tertile 1 (low crime) | Tertile 2 (medium crime) | Tertile 3 (high crime) | ||
| N | 34 383 | 11 345 | 11 690 | 11 348 |
| Mother’s age at delivery—Mean (SD) | 31.1 (5.4) | 32.5 (4.6) | 30.7 (5.6) | 30.0 (5.8) |
| Race | ||||
| White | 17 063 (49.6) | 7669 (67.6) | 5246 (44.9) | 4148 (36.6) |
| Hispanic/Latino | 6193 (18.0) | 1002 (8.8) | 3235 (27.7) | 1956 (17.2) |
| Black/African American | 3792 (11.0) | 316 (2.8) | 621 (5.3) | 2855 (25.2) |
| Asian/Pacific Islander | 2338 (6.8) | 705 (6.2) | 893 (7.6) | 740 (6.5) |
| Other race | 1600 (4.7) | 457 (4.0) | 582 (5.0) | 561 (4.9) |
| Unknown race | 3397 (9.9) | 1196 (10.6) | 1113 (9.5) | 1088 (9.6) |
| Insurance status | ||||
| Private | 26 344 (76.6) | 10 345 (91.2) | 8350 (71.4) | 7649 (67.4) |
| Public | 7825 (22.8) | 950 (8.4) | 3261 (27.9) | 3614 (31.8) |
| None | 214 (0.6) | 50 (0.4) | 79 (0.7) | 85 (0.8) |
| Multiparous | 12 285 (35.7) | 3723 (32.8) | 4241 (36.3) | 4321 (38.1) |
| History of asthma | 3236 (9.4) | 1013 (8.9) | 1042 (8.9) | 1181 (10.4) |
| History of mental health condition | 2758 (8.0) | 1002 (8.8) | 1012 (8.7) | 744 (6.6) |
| History of sexually transmitted disease | 3924 (11.4) | 1261 (11.1) | 1280 (11.0) | 1383 (12.2) |
| History of substance abuse† | 683 (2.0) | 137 (1.2) | 214 (1.8) | 332 (2.9) |
| Prevalent hypertension | 408 (1.2) | 97 (0.9) | 131 (1.1) | 180 (1.6) |
| Prevalent diabetes | 305 (0.9) | 85 (0.8) | 110 (0.9) | 110 (1.0) |
| Gestational diabetes‡ | 1596 (4.6) | 429 (3.8) | 646 (5.5) | 521 (5.0) |
| Infant sex | ||||
| Male | 17 543 (51.0) | 5751 (50.7) | 6003 (51.4) | 5789 (51.0) |
| Female | 16 840 (49.0) | 5594 (49.3) | 5687 (48.6) | 5559 (49.0) |
| Per cent of census tract below poverty level—Mean (SD)§ | 17.3 (11.4) | 11.6 (6.5) | 17.9 (10.7) | 22.5 (13.2) |
| Pregnancy outcomes¶ | ||||
| Hypertensive disease of pregnancy | 1748 (5.1) | 485 (4.3) | 605 (5.2) | 658 (5.8) |
| Preterm birth | 2767 (8.1) | 831 (7.4) | 849 (7.3) | 1087 (9.6) |
| Spontaneous | 1884 (5.5) | 583 (5.2) | 579 (5.0) | 722 (6.4) |
| Induced | 883 (2.6) | 248 (2.2) | 270 (2.3) | 365 (3.2) |
| Small for gestational age | 3573 (10.5) | 1055 (9.4) | 1223 (10.5) | 1295 (11.5) |
*Values are N (%) unless otherwise specified. All demographic/clinical data extracted from electronic medical records. Total neighbourhood crime rate indicates the total number of crime incidents in the year preceding each birth in the mother’s community area of residence per 1000 persons in the community area. Total crime rate was categorised into tertiles for descriptive analyses.
†Including alcohol and tobacco use during current pregnancy.
‡ In current pregnancy.
§Based on the 2009–2013 American Community Survey.
¶Hypertensive disease of pregnancy includes preeclampsia and gestational hypertension. Preterm birth was defined as <37 weeks. Small for gestational age was defined as <10th percentile birth weight for gestational age.