Table 3. Ratio of the odds of delivering an infant too large for gestational age relative to the odds of delivering an infant with appropriate size for gestational age as a function of maternal characteristics, infant sex and gestational age at delivery, Nha Trang, Viet Nam, 2007–2008.
| Characteristic | No.a/totalb (%) | Crude OR | 95% CI | P | Adjusted OR | 95% CI | P |
|---|---|---|---|---|---|---|---|
| Gestational weight gain (kg) | |||||||
| < 10 | 47/625 (7.5) | 0.65 | 0.46–0.92 | 0.014 | 0.72 | 0.50–1.02 | 0.067 |
| ≥ 10 but < 15 | 139/1383 (10.1) | 1.00 | – | – | 1.00 | – | – |
| ≥ 15 | 109/618 (17.6) | 1.97 | 1.51–2.59 | < 0.001 | 1.93 | 1.46–2.57 | < 0.001 |
| BMIc | |||||||
| Low | 37/638 (5.8) | 0.43 | 0.30–0.61 | < 0.001 | 0.51 | 0.35–0.74 | < 0.001 |
| Normal | 205/1758 (11.7) | 1.00 | – | – | 1.00 | – | – |
| High | 53/230 (23.0) | 2.25 | 1.61–3.15 | < 0.001 | 2.04 | 1.43–2.91 | < 0.001 |
| Maternal age (years) | |||||||
| < 24 | 39/715 (5.5) | 0.47 | 0.32–0.69 | < 0.001 | 0.64 | 0.43–0.96 | 0.030 |
| 25–29 | 103/943 (10.9) | 1.00 | – | – | 1.00 | – | – |
| 30–34 | 105/625 (16.8) | 1.65 | 1.23–2.21 | 0.001 | 1.24 | 0.91–1.70 | 0.175 |
| ≥ 35 | 48/343 (14.0) | 1.33 | 0.92–1.92 | 0.131 | 0.98 | 0.66–1.44 | 0.916 |
| Parity | |||||||
| Primipara | 95/1291 (7.4) | 1.00 | – | – | 1.00 | – | – |
| Multipara | 200/1335 (15.0) | 2.22 | 1.72–2.87 | < 0.001 | 1.93 | 1.43–2.61 | < 0.001 |
| Income ( × 1 000 Vietnamese dong) | |||||||
| < 1 500 | 17/223 (7.6) | 0.75 | 0.44–1.28 | 0.288 | 0.93 | 0.53–1.62 | 0.789 |
| ≥ 1 500 but < 2 500 | 92/924 (10.0) | 1.00 | – | – | 1.00 | – | – |
| ≥ 2 500 but < 3 500 | 94/776 (12.1) | 1.25 | 0.92–1.69 | 0.157 | 1.15 | 0.83–1.59 | 0.391 |
| ≥ 3 500 | 92/703 (13.1) | 1.36 | 1.00–1.85 | 0.049 | 1.13 | 0.79–1.61 | 0.507 |
| Education (years) | |||||||
| < 12 | 137/1400 (9.8) | 0.82 | 0.61–1.09 | 0.167 | 0.79 | 0.58–1.09 | 0.791 |
| 12 | 83/707 (11.7) | 1.00 | – | – | 1.00 | – | – |
| > 12 | 75/519 (14.5) | 1.27 | 0.91–1.78 | 0.162 | 1.20 | 0.83–1.72 | 1.197 |
| Total physical activitydin MET h/wk | |||||||
| < 25th percentile | 68/641 (10.6) | 1.01 | 0.71–1.44 | 0.954 | 1.17 | 0.81–1.71 | 0.400 |
| ≥ 25th but < 50th percentile | 68/646 (10.5) | 1.00 | – | – | 1.00 | – | – |
| ≥ 50th but < 75th percentile | 82/669 (12.3) | 1.19 | 0.85–1.67 | 0.319 | 1.09 | 0.76–1.56 | 0.658 |
| ≥ 75th percentile | 77/669 (11.5) | 1.11 | 0.78–1.57 | 0.563 | 0.90 | 0.63–1.30 | 0.587 |
| Smoking exposure | |||||||
| None | 198/1720 (11.5) | 1.00 | – | – | 1.00 | – | – |
| Passive indoor smoking | 97/906 (10.7) | 0.92 | 0.71–1.19 | 0.535 | 1.08 | 0.82–1.42 | 0.576 |
| Infant sex (male = 1, female = 0) | 171/1383 (12.4) | 1.27 | 1.00–1.63 | 0.053 | 1.22 | 0.95–1.58 | 0.120 |
| Gestational age at delivery | – | 1.01e | 0.91–1.13 | 0.797 | 1.00 | 0.89–1.12 | 0.964 |
BMI, body mass index; CI, confidence interval; MET h/wk, metabolic equivalent hours per week; OR, odds ratio.
a This represents the number of infants too large for gestational age (n = 295) born to women with the characteristic.
b This represents the number of infants of appropriate size plus the number of infants too large for gestational age (n = 2626) born to women with the characteristic.
c BMI represents body weight in kilograms divided by body surface area in square metres. Categories: low BMI: < 18.5; normal BMI, ≥ 18.5 but < 23.0; high BMI, ≥ 23.0.
d There is one case with missing data for physical activity.
e This OR represents the change in the risk of delivering a large baby with each additional week of gestation.