Table 1. Baseline characteristics.
| PG | CG | BG | |
| N = 414 | N = 416 | N = 300 | |
| Age at enrollment/randomization (days) | 30 (20–42) | 32 (21–45) | 50 (36–54) |
| Birth weight (grams) | 3277 (2965–3610) | 3320 (2930–3625) | 3438 (3110–3678) |
| Gestational age (completed weeks) | 39 (38–40) | 39 (38–40) | 40 (39–40) |
| Boys | 220 (53%) | 200 (48%) | 134 (45%) |
| White race | 378 (91%) | 392 (94%) | 287 (96%) |
| Vaginal delivery | 261 (63%) | 272 (65%) | 247 (82%) |
| Caesarean Section (incl. Elective) | 153 (37%) | 144 (35%) | 53 (18%) |
| Rooms in household (not kitchen/bathroom) | 3 (3–4) | 3 (3–4) | 4 (3–5) |
| Number of children in household | 2 (1–2) | 2 (1–2) | 2 (1–2) |
| Single parent family | 25 (6%) | 23 (6%) | 17 (6%) |
| Furry pets in household | 133 (32%) | 150 (36%) | 95 (32%) |
| Smoking mother | 79 (19%) | 81 (19%) | 21 (7%) |
| Smoking father | 142 (35%) | 163 (40%) | 81 (27%) |
| Education level of the mother | |||
| primary and secondary school | 206 (50%) | 208 (50%) | 115 (38%) |
| some university education/some postsecondary education/technical or trade qualification | 138 (33%) | 119 (29%) | 107 (36%) |
| completed university degree | 69 (17%) | 89 (21%) | 78 (26%) |
| Mother employed | 252 (61%) | 269 (65%) | 207 (69%) |
| Education level of the father | |||
| primary and secondary school | 184 (46%) | 188 (46%) | 101 (34%) |
| some university education/some postsecondary education/technical or trade qualification | 142 (35%) | 127 (31%) | 113 (38%) |
| completed university degree | 77 (19%) | 95 (23%) | 85 (28%) |
| Father employed | 369 (92%) | 377 (92%) | 283 (95%) |
For continuous variables: median (25–75 percentile) values.
For categorical data: percentages.
PG = prebiotics group; CG = control group; BG = breastfeeding group.