Table 1.
Maternal baseline characteristics stratified by the pre-pregnancy BMI (pBMI) (n 1456)
| Variable | pBMI | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UW (n 140) | NW (n 891) | OW (n 230) | OB (n 195) | P value† | P value‡ | P value§ | ||||||
| n | % | n | % | n | % | n | % | P for trend * | UW v. OB | NW v. OB | OW v. OB | |
| Basic characteristic | ||||||||||||
| Age (years) | ||||||||||||
| Mean | 31·6 | 32·6 | 32·8 | 33·0 | 0·005 | 0·009 | 0·272 | 0·557 | ||||
| sd | 4·6 | 4·6 | 4·8 | 5·0 | ||||||||
| pBMI (kg/m2) | ||||||||||||
| Mean | 17·7 | 21·1 | 25·3 | 30·5 | <0·001 | <0·001 | <0·001 | <0·001 | ||||
| sd | 0·6 | 1·5 | 0·9 | 3·1 | ||||||||
| Trimester | ||||||||||||
| First trimester | 32 | 22·9 | 226 | 25·4 | 56 | 24·3 | 48 | 24·6 | 0·562 | |||
| Second trimester | 45 | 32·1 | 286 | 32·1 | 85 | 37·0 | 55 | 28·2 | ||||
| Third trimester | 63 | 45·0 | 379 | 42·5 | 89 | 38·7 | 92 | 47·2 | ||||
| Parity | ||||||||||||
| Primiparous | 87 | 62·1 | 518 | 58·3 | 112 | 48·7 | 78 | 40·0 | <0·001 | |||
| Blood biomarkers | ||||||||||||
| Hb (g/dl) | ||||||||||||
| Mean | 11·4 | 11·7 | 12·1 | 11·7 | 0·067 | 0·043 | 0·284 | 0·275 | ||||
| sd | 1·7 | 1·9 | 2·2 | 1·9 | ||||||||
| TS (%) | ||||||||||||
| Mean | 17·8 | 16·9 | 16·6 | 13·7 | <0·001 | 0·013 | <0·001 | <0·001 | ||||
| sd | 12·7 | 10·2 | 8·4 | 7·5 | ||||||||
| SF (ng/ml)‖ | 11·6 | 7·6–26·3 | 13·1 | 7·9–27·5 | 15·1 | 8·8–31·5 | 14·8 | 7·8–32·4 | 0·032 | 0·133 | 0·29 | 0·727 |
| Serum hepcidin (ng/ml) | ||||||||||||
| Mean | 20·1 | 23·3 | 26·1 | 27·7 | 0·02 | 0·002 | 0·037 | 0·37 | ||||
| sd | 31·0 | 31·6 | 35·0 | 34·0 | ||||||||
| Folate (ng/ml) | ||||||||||||
| Mean | 13·0 | 13·0 | 12·8 | 11·8 | 0·018 | 0·014 | <0·001 | 0·007 | ||||
| sd | 7·5 | 7·1 | 7·4 | 7·3 | ||||||||
| Vitamin B12 (pg/ml)‖ | 306 | 230–385 | 283 | 212–381 | 275 | 202–367 | 241 | 180–356 | 0·002 | <0·001 | <0·001 | 0·045 |
| Erythropoiesis-related nutrition deficiencies | ||||||||||||
| Anaemia | 42 | 30·0 | 226 | 25·4 | 40 | 17·4 | 49 | 25·1 | 0·108 | 0·323 | 0·939 | 0·051 |
| Anaemia non-ID1 | 9 | 6·4 | 66 | 7·4 | 13 | 5·7 | 4 | 2·1 | 0·017 | 0·041 | 0·006 | 0·059 |
| Anaemia non-ID | 11 | 7·9 | 77 | 8·7 | 21 | 9·1 | 14 | 7·2 | 0·769 | 0·816 | 0·502 | 0·466 |
| IDA1 | 33 | 23·6 | 160 | 18·0 | 27 | 11·7 | 45 | 23·1 | 0·782 | 0·916 | 0·098 | 0·002 |
| IDA | 31 | 22·1 | 149 | 16·7 | 19 | 8·3 | 35 | 17·9 | 0·097 | 0·341 | 0·684 | 0·003 |
| ID1 | 72 | 51·4 | 466 | 52·3 | 122 | 53·0 | 138 | 70·8 | <0·001 | <0·001 | <0·001 | <0·001 |
| ID | 60 | 42·9 | 384 | 43·1 | 82 | 35·7 | 89 | 45·6 | 0·853 | 0·613 | 0·525 | 0·036 |
| Folate depletion | 31 | 22·1 | 152 | 17·1 | 44 | 19·1 | 57 | 29·2 | 0·008 | 0·146 | <0·001 | 0·015 |
| Vit B12 deficiency | 21 | 15·0 | 199 | 22·3 | 57 | 24·8 | 67 | 34·4 | <0·001 | <0·001 | <0·001 | 0·03 |
UW, underweight; NW, normal weight; OW, overweight; OB, obese; TS, transferrin saturation; SF, serum ferritin; ID, iron deficiency; IDA, iron deficiency anaemia; Vit, vitamin; 1, no serum ferritin.
Continuous data are presented as the mean ± sd; categorical data are presented as the number (percentage of the same group).
UW, pBMI of <18·5 kg/m2; NW, pBMI of 18·5–23·9 kg/m2; OW, pBMI of 24–26·9 kg/m2; OB, pBMI of ≥27 kg/m2.
P for trend was analysed by a general linear model/one-way ANOVA for continuous variables and chi-squared test for categorical variables (P < 0·05).
P value (UW compared to OB).
P value (OW compared to OB).
P value (NW compared to OB).
Median (interquartile range) is given because of the skewed distribution of the variable.
The P value was analysed by the Mann–Whitney U test for continuous variables and chi-squared test for categorical variables (P < 0·05).