TABLE 2.
Sample characteristics with significant differences by sex and by SGA statusa
| Total n = 383 |
Males n = 192 |
Females n = 191 |
Not SGA n = 350 |
SGA n = 33 |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Variable | Mean or Freq |
SD or % |
Mean or Freq |
SD or % |
Mean or Freq |
SD or % |
Mean or Freq |
SD or % |
Mean or Freq |
SD or % |
Sex Diffb P value |
SGA Diffb P value |
| Small for gestational age | 33 | 8.6% | 13 | 6.8% | 20 | 10.5% | 0.20 | |||||
| Gestational age at birth (weeks) | 39.6 | 1.2 | 39.6 | 1.2 | 39.6 | 1.1 | 39.6 | 1.2 | 39.8 | 1.1 | 0.74 | 0.29 |
| Birth weight (g) | 3054.1 | 365.6 | 3113.7 | 348.0 | 2994.2 | 373.9 | 3110.7 | 323.3 | 2453.9 | 222.3 | <0.01 | <0.001 |
| Maternal age (years) | 30.4 | 4.0 | 30.4 | 4.2 | 30.3 | 3.7 | 30.5 | 4.0 | 29.2 | 3.4 | 0.79 | 0.07 |
| Maternal height (cm) | 157.7 | 5.5 | 157.8 | 5.3 | 157.5 | 5.7 | 158.0 | 5.4 | 154.9 | 5.8 | 0.59 | <0.01 |
| Maternal pre-pregnancy weight (kg) | 51.6 | 6.7 | 51.8 | 6.3 | 51.4 | 7.0 | 51.9 | 6.7 | 48.2 | 5.2 | 0.54 | <0.01 |
| Maternal pre-pregnancy BMI (kg/m2) | 20.7 | 2.5 | 20.8 | 2.3 | 20.7 | 2.7 | 20.8 | 2.5 | 20.1 | 2.0 | 0.77 | 0.12 |
| Parity | 0.39 | 0.07 | ||||||||||
| 0 | 188 | 49.1% | 100 | 52.1% | 88 | 46.1% | 166 | 47.4% | 22 | 66.7% | ||
| 1 | 132 | 34.5% | 60 | 31.3% | 72 | 37.7% | 123 | 35.1% | 9 | 27.3% | ||
| 2 or more children | 63 | 16.5% | 32 | 16.7% | 31 | 16.2% | 61 | 17.4% | 2 | 6.1% | ||
| Primiparity (# primparous) | 188 | 49.1% | 100 | 52.1% | 88 | 46.1% | 166 | 47.4% | 22 | 66.7% | 0.24 | 0.03 |
| Maternal Smoking (# current or past)c | 8 | 2.2% | 4 | 2.2% | 4 | 2.2% | 8 | 2.4% | 0 | 0.0% | 0.99 | 0.38 |
| GWG | 9.4 | 3.5 | 9.5 | 3.3 | 9.3 | 3.7 | 9.5 | 3.4 | 8.3 | 3.9 | 0.73 | 0.06 |
| GWG adequacyd | 0.79 | 0.07 | ||||||||||
| inadequate | 83 | 21.7% | 39 | 20.3% | 44 | 23.0% | 71 | 20.3% | 12 | 36.4% | ||
| adequate | 224 | 58.5% | 115 | 59.9% | 109 | 57.1% | 210 | 60.0% | 14 | 42.4% | ||
| excessive | 76 | 19.8% | 38 | 19.8% | 38 | 19.9% | 69 | 19.7% | 7 | 21.2% | ||
a
For dichotomous variables, P-values are derived from two-sided asymptotic Pearson Chi-Square tests. For continuous variables, P-values are derived from t-tests. Significant sex and and SGA differences are shown with significant P-values (P<0.05) in bold.
b
Welch robust test (which does not assume equality of variance) gave similar results to t-tests.
c
Smoking status was missing for 24 mothers. N=359 (total), 180 (male), 179 (female), 328 (not SGA), 31 (SGA).
d
Adequacy assessed by Japanese guidelines (see Table 1)
Abbreviations: BMI= body mass index; GWG=gestational weight gain