Maternal multiple micronutrient supplementation and pregnancy outcomes in developing countries: meta-analysis and meta-regression
Kosuke Kawai, Donna Spiegelman, Anuraj H Shankar & Wafaie W Fawzi
Volume 89, Number 6, June 2011, 402-411B
Table 3. Subgroup analysis and meta-regression for the effect of maternal micronutrient supplements on birth weight in developing countries
| Characteristic | No. of trials | Mean difference in birth weight in g (95% CI) | Univariate meta-regression |
||
|---|---|---|---|---|---|
| P-value for test for heterogeneity by covariate | Residual I2 after adjusting for covariate (P-value) | Reduction in I2 after adjusting for covariate (%) | |||
| Average gestational age at initiation of supplements | 0.22 | 57% (0.003) | 0 | ||
| < 20 weeks | 9 | 35 (14–57) | – | – | – |
| ≥ 20 weeks | 6 | 60 (33–86) | – | – | – |
| No maternal education | 0.43 | 56% (0.01) | 7 | ||
| < 50% | 9 | 39 (18–60) | – | – | – |
| ≥ 50% | 4 | 50 (23–78) | – | – | – |
| Iron dose in treatment and control groups | 0.99 | 57% (0.003) | 0 | ||
| Same | 7 | 45 (17–73) | – | – | – |
| Different | 8 | 45 (23–66) | – | – | – |
| Maternal underweighta | 0.37 | 56% (0.01) | 1 | ||
| < 20% | 11 | 47 (30–63) | – | – | – |
| ≥ 20% | 4 | 43 (−5–90) | – | – | – |
| Average maternal height | 0.08 | 43% (0.05) | 25 | ||
| < 155 cm | 7 | 27 (6–49) | – | – | – |
| ≥ 155 cm | 8 | 59 (43–75) | – | – | – |
| Primiparas | 0.20 | 51% (0.01) | 11 | ||
| < 35% | 8 | 53 (29–78) | – | – | – |
| ≥ 35% | 7 | 37 (15–58) | – | – | – |
CI, confidence interval.
a Body mass index (weight in kg divided by square of height in metres) < 18.5.