Table 1.
Mean (SD) and frequency (%) for maternal and child characteristics by RWG group (total n = 10 637)
| Non-RWG | RWG | P * | |
|---|---|---|---|
| (n = 6137) | (n = 4500) | ||
| Birth weight-for-gestational-age | <0.001 | ||
| SGA | 130 (2.1%) | 801 (17.8%) | |
| AGA | 5010 (81.6%) | 3635 (80.7%) | |
| LGA | 997 (16.2%) | 64 (1.4%) | |
| Maternal pre-pregnancy BMI (kg/m2) | 23.81 (4.41) | 23.61 (4.40) | 0.01 |
| Maternal smoking in pregnancy | <0.001 | ||
| No | 5029 (82.0%) | 3204 (71.2%) | |
| Yes (>0 cigarette/day) | 1108 (18.1%) | 1296 (28.8%) | |
| Birth order | <0.001 | ||
| First-born | 2317 (37.8%) | 2192 (48.7%) | |
| Second or later born | 3820 (62.3%) | 2308 (51.3%) | |
| Duration of exclusive breastfeeding | 0.011 | ||
| None | 1858 (30.3%) | 1427 (31.7%) | |
| 0–4 months | 4034 (65.7%) | 2938 (65.3%) | |
| 4 months or longer | 245 (4.0%) | 135 (3.0%) | |
| Early introduction to solid foods (<4 months) | 0.52 | ||
| Yes | 2252 (36.7%) | 1624 (36.1%) | |
| No | 3885 (63.3%) | 2876 (63.9%) | |
| Mother’s highest academic qualifications | <0.001 | ||
| Diploma or degree | 1801 (29.4%) | 1197 (26.6%) | |
| A-level | 666 (10.9%) | 450 (10.0%) | |
| GCSE grades A*–C | 2117 (34.5%) | 1541 (34.2%) | |
| GCSE grades D–G | 600 (9.8%) | 490 (10.9%) | |
| Others | 138 (2.3%) | 98 (2.2%) | |
| None | 815 (13.3%) | 724 (16.1%) | |
| Family income quintiles | <0.001 | ||
| Lowest quintile | 1074 (17.5%) | 973 (21.6%) | |
| Second quintile | 1297 (21.1%) | 938 (20.8%) | |
| Third quintile | 1270 (20.7%) | 857 (19.0%) | |
| Fourth quintile | 1274 (20.8%) | 923 (20.5%) | |
| Highest quintile | 1222 (19.9%) | 809 (18.0%) | |
| Ethnicity | <0.001 | ||
| White | 5503 (90.0%) | 3798 (84.4%) | |
| South Asian | 339 (5.5%) | 369 (8.2%) | |
| Black | 71 (1.2%) | 135 (3.0%) | |
| Others | 224 (3.7%) | 198 (4.4%) | |
*
P-values for difference between RWG and non-RWG groups based on t-test for continuous variables and on chi-squared test for categorical variables.
RWG: rapid weight gain; SGA/AGA/LGA: small-/appropriate-/large-for-gestational-age.