Table 5.
Multiple linear regression for Symphysis-fundal height (SFH) Z-scores, with (A) mean arterial pressure (MAP) and hemoglobin (grams/dL) and (B) diastolic blood pressure (DBP) and hematocrit (%).
| A. SFH Z-scorea,c | Non-standardized Coef. ± SE | P | 95% CI | Standardized β-coef. | Overall model |
|---|---|---|---|---|---|
| History of displacement | −1.01 ± 0.31 | 0.001 | −1.72, −0.48 | −0.36 | P = 0.0010 Adj. R2 = 0.262 |
| MAP, centileb | 0.49 ± 0.20 | 0.017 | 0.09, 0.89 | 0.30 | |
| Hemoglobin, grams/dL | 0.36 ± 0.21 | 0.096 | −0.07, 0.79 | 0.21 | |
| Taking iron supplements (0 = no, 1 = yes) | 0.54 ± 0.29 | 0.073 | −0.05, 1.39 | 0.22 | |
| Constant | −3.40 ± 0.62 | <0.0001 | −4.65, −2.14 | ||
| B. SFH Z-scorea, c | Non-standardized Coef. ± SE | P | 95% CI | Standardized β-coef. | Overall model |
| History of displacement | −1.09 ± 0.31 | 0.001 | −1.72, −0.48 | −0.41 | P < 0.0001 Adj. R2 = 0.379 |
| Taking iron supplements (0 = no, 1 = yes) | 0.59 ± 0.28 | 0.041 | 0.02, 1.15 | 0.24 | |
| Hematocrit, centile | 0.47 ± 0.18 | 0.014 | 0.10, 0.84 | 0.29 | |
| Diastolic blood pressure, centileb | 0.91 ± 0.25 | 0.001 | 0.39, 1.43 | 0.41 | |
| Constant | −4.37 ± 0.65 | <0.0001 | −5.68, −3.06 |
Variables that were included but were not retained in the final models (P > 0.10): # sleep hours (score), eating nuts/avocado at least once/week (0 = no, 1 = yes), history of hypertensive disorders of pregnancy (0 = no, 1 = yes).
Model A: n = 52. VIF = 1.02. Condition number: 10.63.
Model B: n = 50. VIF = 1.03. Condition number: 12.41.
25th and 75th centiles of MAP, DBP, hemoglobin and hematocrit were calculated from our population and used instead of continuous variables in order correct for non-linear associations: MAP: <73, between 73 and 83 and >83 mmHg, DBP: <60, between 60 and 70 and >70 mmHg; hemoglobin: <12, ≥12 and ≤13.7, >13.7 grams/dL; hematocrit: <35.7, ≥35.7 and ≤41.2, >41.2%.
After 50 bootstrap replications of linear regression models we observed that percentile- and bias-corrected confidence intervals were similar (Table S3).