Table 4.
Meta-analyses of RCTs supplementing pregnant women with micronutrients: pregnancy and early-life postnatal outcomes
| Micronutrient | Outcome (quality of evidence per meta-analysis: low; moderate; high)* |
|||
|---|---|---|---|---|
| During pregnancy |
At Birth | < 1 month | < 5 years | |
|
|
||||
| Vitamins | ||||
| Vitamin A4 (McCauley 2015157) |
No effect: stillbirth |
No effect: preterm birth, low birth weight |
No effect: neonatal mortality |
– |
|
| ||||
| Vitamin B6 (Salam 2015158) |
No effect: preeclampsia |
– | – | – |
|
| ||||
| Folic acid (De-Regil 201092) |
72% ↓ risk NTD (low) No effect: other birth defects, miscarriage |
– | – | – |
|
| ||||
| Folic acid (Lassi 2013103) |
No effect: stillbirth |
136 g ↑ birth weight (high) No effect: low birth weight |
No effect: neonatal mortality |
– |
|
| ||||
| Vitamin C‡ (Rumbold 2015159) |
No effect: stillbirth, preeclampsia |
36% ↓ risk preterm PROM (high) No effect: preterm birth; IUGR |
No effect: neonatal mortality |
– |
|
| ||||
| Vitamin D∥ (De-Regil 2016105) |
No effect: stillbirth, preeclampsia |
60% ↓ risk low birth weight (moderate); 64% ↓ risk preterm birth (moderate) No effect: preterm birth, birth weight, SGA |
No effect: neonatal mortality |
– |
|
| ||||
| Minerals | ||||
| Iodine (Bougma 2013130 and Zhou 2013129) |
– | – | – | 8 ↑ IQ points (high); ↓ risk cretinism |
|
| ||||
| Iron§ (Peña-Rosas 2015102) |
No effect: birth defects |
No effect: preterm birth, birth weight, low birth weight |
No effect: neonatal mortality |
– |
|
| ||||
| Iron/IFA (Haider 2013101) |
– | 41 g ↑ birth weight (low); 19% ↓ risk low birth weight (low) No effect: preterm birth, SGA |
– | – |
|
| ||||
| Zinc (Ota 2015111) |
No effect: stillbirth, preeclampsia, birth defects |
14% ↓ risk preterm birth (moderate) No effect: birth weight, low birth weight, SGA |
No effect: neonatal mortality |
– |
Most outcomes presented were not assessed in all trials (for example, birth weight was only assessed in five of 31 folic acid trials). Improvements in biochemical status or clinical issues that are not specific to pregnancy (such as nightblindness or anaemia) are not presented. IFA, iron-folic acid; IUGR, intrauterine growth restriction; PROM, premature rupture of the chorioamniotic membrane; RCT, randomized controlled trial; SGA, small for gestational age.
Quality of evidence is defined by the original meta-analysis.
Only includes trials comparing groups with vitamin C to groups without vitamin C (does not include trials of vitamin C and vitamin E tested together).
Only includes trials comparing groups with vitamin D to groups without vitamin D.
Only includes trials comparing groups with iron to groups without iron, does not include trials of iron and folic acid tested together.