Table 3. Odds ratios (ORs) for birthweight according to pre-pregnancy body mass index (BMI) and gestational weight gain (GWG).
| Maternal weight status | Birth outcomes | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| High birthweight (Macrosomia) n = 505 with 35 case | Small for gestational age (SGA) n = 456 with 32 case | Large for gestational age (LGA) n = 478 with 54 case | |||||||
| n | Crude OR (95% CI) | Adjusted OR (95% CI)b | n | Crude OR (95% CI) | Adjusted OR (95% CI)b | n | Crude OR (95% CI) | Adjusted OR (95% CI)b | |
| Pre-pregnancy BMI | |||||||||
| Underweight | 118 (3) | 0.31 (0.09, 1.04) | 0.34 (0.10, 1.22) | 115 (8) | 0.88 (0.38, 2.04) | 0.94 (0.40, 2.23) | 112 (5) | 0.31 (0.12, 0.81)* | 0.32 (0.12, 0.86)* |
| Normal weight | 333 (26) | Referent | Referent | 295 (23) | Referent | Referent | 313 (41) | Referent | Referent |
| Overweight/Obese | 54 (6) | 1.48 (0.58, 3.78) | 1.28 (0.44, 3.75) | 46 (1) | 0.26 (0.04, 2.00) | 0.17 (0.02, 1.34) | 53 (8) | 1.18 (0.52, 2.68) | 1.04 (0.42, 2.56) |
| GWG by the 2009 IOM recommendationsa | |||||||||
| Inadequate | 103 (6) | 3.36 (0.93, 12.16) | 4.28 (0.95, 17.03) | 98 (15) | 2.54 (1.18, 5.50)* | 3.60 (1.57, 8.30)** | 90 (7) | 1.51 (0.57, 4.03) | 1.76 (0.64, 4.85) |
| Adequate | 221 (4) | Referent | Referent | 211 (14) | Referent | Referent | 208 (11) | Referent | Referent |
| Excessive | 181 (25) | 8.69 (2.97, 25.48)** | 7.49 (2.42, 23.19)** | 147 (3) | 0.29 (0.08, 1.04) | 0.28 (0.08, 1.02) | 180 (36) | 4.48 (2.20, 9.09)** | 3.79 (1.82, 7.90)** |
aGWG within the IOM recommendations were 12.5–18, 11.5–16, 7–11.5, and 5–9 kg for underweight, normal weight, overweight, and obese women, respectively.
bPre-pregnancy BMI and GWG were mutually adjusted and also adjusted for maternal age, education, parity, smoking, alcohol use, infant sex, household monthly salary, and gestational age.
*p < 0.05; **p < 0.01.