Characteristics of ALSPAC participants included in analysis, by maternal anxiety levels during pregnancy
| No anxiety during pregnancy n=6137 | Anxiety at 18 weeks gestation only n=651 | Anxiety at 32 weeks gestation only n=792 | Anxiety at 18 and 32 weeks gestation n=1026 | |
| n (%) | n (%) | n (%) | n (%) | |
| Household social class* | ||||
| Professional | 936 (15.3) | 74 (11.4) | 87 (11.0) | 93 (9.1) |
| Managerial and technical | 2673 (43.6) | 282 (43.3) | 310 (39.1) | 408 (39.8) |
| Non-manual | 1574 (25.6) | 174 (26.7) | 222 (28.0) | 284 (27.7) |
| Manual | 677 (11.0) | 86 (13.2) | 107 (13.5) | 167 (16.3) |
| Part skilled and unskilled | 277 (4.5) | 35 (5.4) | 66 (8.3) | 74 (7.2) |
| Maternal education | ||||
| Less than O level | 1410 (23.0) | 152 (23.3) | 249 (31.4) | 313 (30.5) |
| O level† | 2228 (36.3) | 257 (39.5) | 273 (34.5) | 409 (39.9) |
| A level | 1549 (25.2) | 167 (25.7) | 170 (21.5) | 207 (20.2) |
| Degree or above | 950 (15.5) | 75 (11.5) | 100 (12.6) | 97 (9.5) |
| Mother’s partner’s highest educational qualification | ||||
| Less than O level | 1675 (28.0) | 189 (30.0) | 272 (35.9) | 352 (36.1) |
| O level† | 1320 (22.1) | 151 (24.0) | 176 (23.2) | 225 (23.1) |
| A level | 1711 (28.6) | 167 (26.6) | 196 (25.9) | 263 (26.9) |
| Degree or above | 1271 (21.3) | 122 (19.4) | 114 (15.0) | 136 (13.9) |
| Maternal smoking during pregnancy | ||||
| No | 5040 (82.1) | 480 (73.7) | 587 (74.1) | 674 (65.7) |
| Yes | 1097 (17.9) | 171 (26.3) | 205 (25.9) | 352 (34.3) |
| Parity | ||||
| 0 | 2795 (45.5) | 319 (49.0) | 352 (44.4) | 427 (41.6) |
| 1 | 2286 (37.2) | 220 (33.8) | 289 (36.5) | 364 (35.5) |
| 2 | 1056 (17.2) | 112 (17.2) | 151 (19.1) | 235 (22.9) |
| Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | |
| Gestational age (weeks) | 39.5 (1.8) | 39 (1.7) | 39 (1.6) | 39 (1.8) |
| Birth weight (g) | 3431(535) | 3395(527) | 3417(500) | 3423(546) |
| Pre-pregnancy BMI (kg/m2) | 22.9 (3.7) | 23 (4.2) | 23 (3.8) | 23 (4.0) |
| Maternal age (years) | 29.0 (4.5) | 28 (4.9) | 28 (5.0) | 28 (4.9) |
Number of participants available for analyses of BMI (n=8606) used as the denominator in this table given the varying sample sizes included in analyses.
*Household social class was measured as the highest of the mother’s or her partner’s occupational social class using data on job title and details of occupation collected about the mother and her partner from the mother’s questionnaire at 32 weeks gestation. Social class was derived using the standard occupational classification codes developed by the United Kingdom Office of Population Census and Surveys and classified as I professional, II managerial and technical, IIINM non-manual, IIIM manual, and IV and V part skilled occupations and unskilled occupations
†O levels equate to current General Certificate of Secondary Education (GCSEs) demonstrating education level at aged 16.
ALSPAC, Avon Longitudinal Study of Parents and Children; BMI, body mass index.