Table 1. Demographic Characteristics of the Study Populationa.
| Characteristic | Term birth (n = 2718) | Preterm birth (n = 138) | Postterm birth (n = 223) |
|---|---|---|---|
| Maternal characteristics | |||
| Age at intake, mean (SD), y | 31.0 (4.9) | 30.7 (5.1) | 31.4 (4.5) |
| Multiparous | 323 (11.9) | 17 (12.3) | 23 (10.3) |
| Pregnancy complicationsb | 179 (6.6) | 22 (15.9) | 11 (4.9) |
| Ethnicity | |||
| Dutch | 1569 (57.7) | 70 (50.7) | 132 (59.2) |
| Non-Dutch, Western | 323 (11.9) | 16 (11.6) | 36 (16.1) |
| Non-Dutch, non-Western | 826 (30.4) | 52 (37.7) | 55 (24.7) |
| Educational level | |||
| Primary or lower | 195 (7.2) | 13 (9.4) | 13 (5.8) |
| Secondary | 1112 (40.9) | 72 (52.2) | 82 (36.8) |
| Higher | 1411 (51.9) | 53 (38.4) | 128 (57.4) |
| Monthly household income, US$ | |||
| <1550 | 423 (15.6) | 33 (23.9) | 34 (15.2) |
| 1550-2580 | 463 (17.0) | 34 (24.6) | 23 (10.3) |
| >2580 | 1832 (67.4) | 71 (51.4) | 166 (74.4) |
| Marital status (married or with partner) | 2405 (88.5) | 109 (79.0) | 202 (90.6) |
| Smoking during pregnancy | |||
| Never in pregnancy | 2101 (77.3) | 104 (75.4) | 176 (78.9) |
| Until pregnancy was known | 231 (8.5) | 10 (7.2) | 23 (10.3) |
| Continued in pregnancy | 386 (14.2) | 24 (17.4) | 24 (10.8) |
| Alcohol use during pregnancy | |||
| Never in pregnancy | 1093 (40.2) | 53 (38.4) | 89 (39.9) |
| Until pregnancy was known | 380 (14.0) | 22 (15.9) | 25 (11.2) |
| Continued in pregnancy, occasionally | 985 (36.2) | 49 (35.5) | 85 (38.1) |
| Continued in pregnancy, frequentlyc | 260 (9.6) | 14 (10.1) | 24 (10.8) |
| Psychopathologic symptoms, mean (SD) | 0.3 (0.4) | 0.4 (0.4) | 0.3 (0.4) |
| Birth and child characteristics | |||
| Cesarean delivery | 306 (11.3) | 33 (23.9) | 43 (19.3) |
| Suspected fetal distress | 195 (7.2) | 15 (10.9) | 27 (12.1) |
| Apgar score at 5 min <7 | 28 (1.0) | 4 (2.9) | 2 (0.9) |
| Gestational age at birth, mean (SD) [range], wk | 40.0 (1.1) [37.0-41.9] | 34.6 (2.7) [26.3-36.9] | 42.3 (0.3) [42.0-43.4] |
| Birth weight, mean (SD), g | 3472.6 (485.9) | 2345.6 (654.7) | 3785.7 (475.6) |
| Male | 1340 (49.3) | 65 (47.1) | 128 (57.4) |
| Age at MRI, mean (SD), y | 10.1 (0.6) | 10.2 (0.6) | 10.1 (0.6) |
Abbreviation: MRI, magnetic resonance imaging.
a
Data are presented as number (percentage) of study participants unless otherwise indicated. No data were missing for these variables because they were imputed using multiple imputation methods. Categorization was based on gestational age at birth: term birth (gestational age of 37-42 weeks), preterm birth (gestational age <37 weeks), and postterm birth (gestational age of ≥42 weeks).
b
Pregnancy complications included preeclampsia, diabetes, and/or pregnancy-induced hypertension.
c
Frequent continued alcohol use is defined as 1 or more glasses of alcohol per week in at least 2 trimesters.