Table 3.
Birth weight for gestational age percentiles and gestational age and risk of intellectual disability in non-malformed, term or post-term, appropriate-for-gestational-age children, using children born at 40 weeks and with a birth weight for gestational age from 40th to 59th percentile as the reference group (Population analysis, complete case analysis) (N = 721,094)
| Gestational age (weeks) | Birth weight for gestational age percentiles | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 10th–24th | 25th–39th | 40th–59th | 60th–74th | 75th–90th | ||||||
| No. of cases/children | HR (95%CI) | No. of cases/children | HR (95%CI) | No. of cases/children | HR (95%CI) | No. of cases/children | HR (95%CI) | No. of cases/children | HR (95%CI) | |
| 37–38 | 62/23,046 | 2.01 (1.43–2.84) | 49/25,018 | 1.48 (1.02–2.15) | 71/34,514 | 1.57 (1.12–2.18) | 56/25,350 | 1.66 (1.16–2.37) | 44/25,069 | 1.28 (0.87–1.87) |
| 39 | 83/31,310 | 2.08 (1.52–2.86) | 70/33,221 | 1.69 (1.21–2.35) | 83/46,100 | 1.46 (1.06–2.00) | 52/32,416 | 1.28 (0.89–1.83) | 52/29,808 | 1.35 (0.95–1.94) |
| 40 | 90/40,715 | 1.74 (1.28–2.38) | 84/43,113 | 1.57 (1.15–2.16) | 71/57,161 | Ref | 62/40,306 | 1.23 (0.88–1.73) | 60/35,868 | 1.30 (0.93–1.84) |
| 41 | 68/28,671 | 1.82 (1.31–2.54) | 75/28,090 | 2.10 (1.52–2.91) | 57/36,890 | 1.21 (0.86–1.72) | 47/25,236 | 1.45 (1.00–2.10)a | 37/22,083 | 1.28 (0.86–1.90) |
| ≥ 42 | 35/13,044 | 1.72 (1.15–2.59) | 29/12,067 | 1.60 (1.04–2.47) | 36/14,606 | 1.66 (1.11–2.50) | 18/9547 | 1.27 (0.75–2.13) | 24/7845 | 2.02 (1.26–3.23) |
Model was adjusted for interaction between gestational age and birth weight for gestational age percentile, maternal age at delivery, parity, educational level, country of birth, smoking during pregnancy, height, BMI in early pregnancy, maternal diabetic and hypertensive diseases, as well as child’s sex, calendar period of delivery, onset of labor, and mode of delivery
aP = 0.048