Association of HBW with categories of maternal pre-pregnancy body mass index (BMI) and gestational weight gain; Chongqing, China, 2012
| Cases: mothers with HBW infants (n=221) | Controls: mothers with NBW infants (n-=221) | Unadjusted | Adjusted* | |||||
|---|---|---|---|---|---|---|---|---|
| Mean±SD † | n | Mean±SD† | n | OR (95% CI) | p Value | OR (95% CI) | p Value | |
| Maternal pre-pregnancy BMI categories | ||||||||
| Normal weight | 21.4±1.4 | 158 | 20.9±1.4 | 149 | 1.00 | 1.00 | ||
| Underweight | 17.7±0.8 | 27 | 17.6±0.6 | 39 | 0.70 (0.39 to 1.27) | 0.241 | 0.86 (0.43 to 1.72) | 0.669 |
| Overweight and obese | 26.5±2.1 | 36 | 27.5±3.8 | 33 | 1.04 (0.62 to 1.74) | 0.895 | 1.16 (0.63 to 2.14) | 0.634 |
| p Trend‡ | 0.198 | 0.364 | ||||||
| GWG categories | ||||||||
| Appropriate | 14.4±2.7 | 35 | 14.0±2.2 | 88 | 1.00 | 1.00 | ||
| Inadequate | 9.3±1.4 | 9 | 9.8±1.3 | 26 | 0.33 (0.04 to 3.21) | 0.341 | 0.19 (0.01 to 3.30) | 0.253 |
| Excessive | 21.3±4.3 | 177 | 19.9±4.4 | 107 | 3.75 (2.29 to 6.14) | <0.001 | 5.39 (2.94 to 9.89) | <0.001 |
| p Trend‡ | <0.001 | <0.001 | ||||||
| GWG among pre-pregnancy normal weight women | ||||||||
| Appropriate | 14.5±1.4 | 21 | 14.2±1.2 | 57 | 1.00 | 1.00 | ||
| Inadequate | 8.9±1.3 | 6 | 9.6±1.3 | 21 | – | – | – | – |
| Excessive | 21.5±3.8 | 131 | 20.3±4.0 | 71 | 5.50 (2.31 to 13.13) | <0.001 | 10.27 (3.20 to 32.95) | <0.001 |
*ORs (95% CI) from conditional logistic model. Covariates include gestational age, gender of newborn, gravidity and family income.
†Mean and SD in each category of maternal pre-pregnancy BMI (kg/m2) and gestational weight gain (kg).
‡The p trend was generated from analysis of linear trends across increasing categories, which were tested by assigning categories as continuous variables in the regression. The sequence of categories was as follows: underweight, normal weight, overweight and obese for maternal pre-pregnancy BMI; and inadequate, appropriate, excessive for gestational weight gain.
GWG, gestational weight gain; HBW, high birth weight; NBW, normal birth weight.