Characteristics of infants according to birth weight status
| Birth weight group | Low for gestation (n = 98) | Appropriate for gestation (n = 136) | 95% CI of difference: low − appropriate |
|---|---|---|---|
| Data shown as mean (SD) for continuous and n (%) for categorical variables. SD scores were calculated using CGF algorithms.10 | |||
| *p<0.05; **p<0.01; ***p<0.001. | |||
| †Age after expected date of delivery. | |||
| ‡84 low birth weight for gestation, 128 appropriate birth weight for gestation. | |||
| ¶86 low birth weight for gestation, 126 appropriate birth weight for gestation. | |||
| §97 low birth weight for gestation, 136 appropriate birth weight for gestation. | |||
| #96 low birth weight for gestation, 133 appropriate birth weight for gestation. | |||
| Boys | 47 (48%) | 72 (53%) | −18 to 8 |
| Infant characteristics at birth | |||
| Gestational age (weeks) | 40.0 (1.5) | 39.8 (1.4) | −0.2 to 0.5 |
| Birth weight (kg) | 2.7 (0.3) | 3.5 (0.4) | −0.8 to −0.7 |
| Birth weight SD score | −1.7 (0.5) | 0.04 (0.5) | −1.8 to −1.6 |
| Crown–heel length (cm)‡ | 49.0 (3.0) | 52.1 (2.7) | −3.9 to −2.3 |
| Crown–heel length SD score‡ | −0.8 (1.4) | 0.9 (1.3) | −2.0 to −1.3 |
| Head circumference (cm)¶ | 33.0 (1.5) | 34.5 (1.3) | −1.9 to −1.1 |
| Maternal and family characteristics | |||
| Maternal age at delivery (years) | 32.0 (5.6) | 32.9 (5.5) | −2.4 to 0.5 |
| Primipara | 65 (66%) | 88 (65%) | −11% to 14% |
| Maternal smoking in pregnancy | 44 (45%) | 51 (38%) | −5% to 20% |
| Maternal weight at booking (kg) | 59.4 (9.7) | 63.4 (10.7) | −6.7 to −1.3** |
| Maternal height (cm)# | 162.3 (6.4) | 164.9 (6.5) | −4.3 to −0.9** |
| Mother in non-manual occupation | 73 (74%) | 110 (81%) | −17% to 4% |
| Father in non-manual occupation§ | 56 (57%) | 98 (72%) | −27% to −3%* |
| Infant characteristics at test | |||
| Age (weeks)† | 6.6 (2.5) | 6.2 (2.0) | −0.2 to 0.9 |
| Weight (kg) | 4.2 (0.8) | 4.8 (0.7) | −0.8 to −0.4*** |
| Weight SD score | −1.1 (0.9) | −0.02 (0.9) | −1.3 to −0.9*** |
| Length (cm) | 54.2 (2.8) | 56.4 (2.6) | −2.9 to −1.5*** |
| Length SD score | −0.8 (0.9) | 0.4 (0.9) | −1.4 to −1.0*** |
| Head circumference (cm) | 38.0 (1.7) | 38.9 (1.5) | −1.4 to −0.5*** |
| Chest circumference (cm) | 37.2 (2.7) | 39.0 (2.2) | −2.5 to −1.2*** |
| Mid arm circumference (cm) | 11.8 (1.4) | 12.4 (1.2) | −0.9 to −0.2** |