Birth weight for gestational age group (n = 820)
| Birth weight for gestational age group | n | Prevalence (%) | 95% CI |
|---|---|---|---|
| AGA | 713 | 86.9 | 84.5, 89.1 |
| SGA | 21 | 2.6 | 1.7, 3.9 |
| LGA | 86 | 10.5 | 8.6, 12.8 |
Prepregnancy baseline and obstetric characteristics of the study population (N = 820)
| Characteristics | n (%) |
|---|---|
| Mean age ± SD (years) | 28.4 ± 6.3 |
| Parity | |
| 0 | 429 (52.3) |
| 1 | 301 (36.7) |
| >2 | 90 (11.0) |
| Mean prepregnancy BMI ± SD (kg/m2) | 21.6 ± 4.0 |
| Prepregnancy BMI category | |
| Normal weight | 518 (63.2) |
| Underweight | 162 (19.8) |
| Overweight | 108 (13.2) |
| Obese | 32 (3.9) |
| Mean gestational weight gain ± SD (kg) | 14.1 ± 4.7 |
| Gestational weight gain category | |
| Adequate | 357 (43.5) |
| Inadequate | 219 (26.7) |
| Excessive | 244 (29.8) |
| Mean gestational age ± SD (weeks) | 38.7 ± 1.1 |
| Mean birth weight ± SD (g) | 3100.7 ± 381.0 |
| Route of delivery | |
| Vaginal delivery | 419 (51.1) |
| Instrument vaginal delivery | 15 (1.8) |
| Cesarean delivery | 386 (47.1) |
| Male infant | 433 (52.8) |
Factors associated with infant birth weight for gestational age
| Characteristics | AGA (n = 713) | SGA (n = 21) | LGA (n = 86) | ANOVA for comparison of means, Chi square test for comparison of proportions |
|---|---|---|---|---|
| Age (years) | 28.3 ± 6.4 | 26.3 ± 6.8 | 29.7 ± 5 . 3 | 0.05 |
| Parity | 0.27 | |||
| 0 | 378 (53%) | 14 (67%) | 37 (43%) | |
| 1 | 257 (36%) | 5 (24%) | 39 (45%) | |
| >2 | 78 (11%) | 2 (10%) | 10 (12%) | |
| Prepregnancy BMI (kg/m2) | 21.5 ± 3.9 | 20.4 ± 5.3 | 22.6 ± 4.0 Significantly different from AGA group by Bonferroni post hoc comparison | 0.02 |
| Prepregnancy BMI category | 0.12 | |||
| Normal weight | 442 (62%) | 15 (71%) | 61 (71%) | |
| Underweight | 151 (21%) | 3 (14%) | 8 (9%) | |
| Overweight | 94 (13%) | 3 (14%) | 11 (13%) | |
| Obese | 26 (4%) | 0 (0) | 6 (7%) | |
| Gestational weight gain (kg) | 13.8 ± 4.6 | 13.9 ± 5.7 | 16.3 ± 4.9 Significantly different from AGA group by Bonferroni post hoc comparison | <0.001 |
| Gestational weight gain category | <0.001 | |||
| Adequate | 318 (45%) | 5 (24%) | 34 (40%) | |
| Inadequate | 200 (28%) | 10 (48%) | 9 (11%) | |
| Excessive | 195 (27%) | 6 (29%) | 43 (50%) | |
| Gestational age (weeks) | 38.7 ± 1.1 | 39.0 ± 1.1 | 38.6 ± 0 . 9 | 0.42 |
| Male infant | 370 (52%) | 11 (52%) | 52 (61%) | 0.32 |
Crude and adjusted odds ratiosAdjusted for prepregnancy BMI and gestational weight gain category, age, parity, gestational age at delivery of factors associated with SGA and LGA
| Risk factors | Crude OR | Adjusted OR | 95%CI | P |
|---|---|---|---|---|
| SGA | ||||
| Prepregnancy BMI category | ||||
| Normal weight | 1.0 | 1.0 | ||
| Underweight | 0.58 | 0.52 | 0.14, 1.87 | 0.31 |
| Overweight or Obese | 0.74 | 0.84 | 0.23, 3.07 | 0.80 |
| Gestational weight gain category | ||||
| Adequate | 1.0 | 1.0 | ||
| Inadequate | 3.18 | 3.20 | 1.06, 9.64 | 0.04 |
| Excessive | 1.96 | 1.69 | 0.50, 5.73 | 0.40 |
| LGA | ||||
| Pre-pregnancy BMI category | ||||
| Normal weight | 1.0 | 1.0 | ||
| Underweight | 0.38 | 0.49 | 0.23, 1.07 | 0.07 |
| Overweight or Obese | 1.03 | 0.82 | 0.45, 1.49 | 0.51 |
| Gestational weight gain category | ||||
| Adequate | 1.0 | 1.0 | ||
| Inadequate | 0.42 | 0.43 | 0.20, 0.91 | 0.03 |
| Excessive | 2.06 | 2.00 | 1.21, 3.30 | 0.01 |