TABLE 3.
Summary of results: maternal and infant secondary outcomes.
| Outcomes | Anticipated absolute effects a (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Certainty of the evidence (GRADE) Comments | |
|---|---|---|---|---|---|
| Risk with no oral iron supplements | Risk with oral iron supplements | ||||
| Maternal severe anemia during pregnancy (Hb concentration below 70 g/L) | 0 per 1.000 | 0 per 1.000 (0–0) | Not estimable | 1407 (4 RCTs) b | ⨁⨁⨁◯ MODERATE c |
| Gestational hypertension | 0 per 1.000 | 0 per 1.000 (0–0) | RR 3.34 (0.14–80.63) | 148 (1 RCT) d | ⨁◯◯◯ VERY LOW e , f |
| Maternal red blood cell transfusion (intra‐ and/or postpartum) | 63 per 1.000 | 21 per 1.000 (1–476) | RR 0.33 (0.01–7.62) | 32 (1 RCT) g | ⨁◯◯◯ VERY LOW e , f |
| Maternal postpartum anemia (Hb concentration <110 g/L) | 80 per 1.000 | 33 per 1.000 (10–105) | RR 0.41 (0.13–1.31) | 223 (1 RCT) h | ⨁⨁◯◯ LOW e , i |
Note: GRADE Working Group grades of evidence. High certainty: We are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect. Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect. The following secondary outcomes are not included in the table as no trials reported them: gestational diabetes, pre‐eclampsia, maternal infections, gastrointestinal side effects, maternal quality of life, maternal fatigue, newborn failure to thrive, newborn Hb concentration in the first 6 months, and newborn ferritin concentration in the first 6 months.
Abbreviations: CI, confidence interval; Hb, hemoglobin; RR, risk ratio.
The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
Cogswell et al. (2003), 16 Ziaei et al. (2008) 17 , Zhao et al. (2015), 20 Alizadeh & Salehi (2016). 21
Several trials contributing data had design limitations.
Falahi et al. (2011). 19
The trial had design limitations.
Wide 95% CI, small sample size and few events.
Puolakka et al. (1980). 13
Tura et al. (1989). 14
Wide 95% CI and small sample size.