Characteristics of interventions
| Review | Intervention | Population | Dose (mean range) | Frequency | Start of intervention |
| McCauley et al24 | Vitamin A | Low-risk and high-risk (women with no, moderate, or severe vitamin A deficiency) | Great variation between trials: 3000–600 000 IU | Daily or weekly | Most studies in second trimester |
| Rumbold et al45 | Vitamin C | Low-risk and high-risk (nine studies recruited women with high or increased risk of pre-eclampsia) | Common dosage 1000 mg (100–2000 mg) | Daily | Most studies in second trimester |
| Rumbold et al46 | Vitamin E | Low-risk and high-risk (nine studies recruited women with high or increased risk of pre-eclampsia) | Common dosage 400 IU (100 mg, 200–800 IU) | Daily | Most studies in second trimester |
| De-Regil et al25 | Folic acid | Women with and without history of neural tube defects | 0.4–4.0 mg | Daily | Periconceptional period (before pregnancy until 12 weeks of pregnancy) |
| Lassi et al26 | Folic acid | Low risk | Common dosage 5 mg (range 0.01–400 mg) | Daily | Initiation varied from 8 weeks of pregnancy until 3 days postpartum |
| An et al27 | Calcium | Low-risk | 1.0–2.0 g | Daily | 11–24 weeks of pregnancy |
| Buppasiri et al28 | Calcium | Low-risk and high-risk (three trials recruited only adolescents) | 1.0 g (range 0.3–2.0 mg) | Daily | Most trials at or after 20 weeks’ gestational age |
| Hofmeyr et al29 | Calcium | Low-risk and high-risk (high-risk of pre-eclampsia; adolescents) | High dose: ≥1 g/day (1.5–2.0 g), low-dose: <1 g/day | Daily | Second trimester |
| Peña-Rosas et al30 | Iron | Low-risk and high-risk (anaemic and non-anaemic women) | 9–900 mg | Daily | Most trials before 20 weeks’ gestation |
| Harding et al31 | Iodine | Low-risk | 75–300 µg | Daily | During pregnancy, postpartum, or pregnancy and postpartum |
| Makrides et al32 | Magnesium | Low-risk and high-risk (pregnancy-induced hypertension, risk of PTB | 365 mg (64–1000 mg) | Daily | Most trials in first trimester |
| Ota et al33 | Zinc | Low-risk and high-risk (one trial recruited women with high risk of SGA) | 5–44 mg (90 mg in one trial) | Daily | Before conception (two trials from 26 weeks’ gestation) |
| Soltani et al34 | Zinc | NA | 20 mg | Daily | 6–20 weeks until delivery |
| Fall et al35 | MMN | Mainly low-risk | MMN formulation that delivered approximately 1 RDA | Daily | In pregnancy |
| Haider et al36 | MMN | Low-risk and high-risk | Different MMN composition in all trials (14 trials included iron and folic acid in MMN) | Daily | Varied (first, second or third trimester) |
| Ramakrishnan et al37 | MMN | Low-risk and high-risk | Most trials used UNIMMAP (1–2 RAD) formulation with 30 mg or 60 mg iron | Daily | First or second trimester |
| Ota et al38 | Protein | Low-risk and high-risk (well-nourished and undernourished women) | Nutritional education Balanced energy/protein: 118–1017 kcal/6–44 g High protein: 40 g | Monthly Daily Daily | Second trimester Second to third trimester Before 30 weeks’ gestation |
| Makrides et al39 | Prostaglandin | Low-risk and high-risk pregnancies | Common dosage: 2.7 g of EPA and DHA | Daily | Commonly after 16 weeks’ gestation |
| Salvig et al40 | n-3 fatty acids | Low-risk and high-risk (previous PTB or IUGR) | 2.7 g | Daily | Low-risk: week 30, high-risk: week 18–21 |
| Duley et al41 | Reduced salt | Low-risk | Low dietary salt: 20 or 50 mmol/day | Daily | 12–20 weeks’ gestation |
| Salamet al42 | Antihelminthics | Low-risk and high-risk (infected with intestinal helminth) | 400 mg albendazole with or without iron/folate or 500 mg mebendazole with iron | Single-dose (iron daily) | Second trimester |
| Radeva-Petrova et al43 | Antimalarials | Low-risk and high-risk | (1) Chloroquine: 300 mg (2) Pyrimethamine: 100 mg/25 mg (3) Proguanil: 100 mg (4) Pyrimethamine-dapsone: 25 mg/100 mg or 12.5 mg/100 mg (5) Sulfadoxine-pyrimethamine: 1500 mg/75 mg (6) Mefloquine: 500 mg loading dose, 250 mg weekly for 4 weeks, 125 mg weekly until delivery | (1) Weekly (2) Monthly/weekly (3) Daily (4) Every 2 weeks or weekly (5) Up to four doses (6) Weekly | From first prenatal visit |
| Muanda et al44 | Antimalarials | Low-risk and high-risk | Any type of antimalarial drug (chloroquine, sulfadoxine-pyrimethamine, mefloquine, dapsone-pyrimethamine) | Two to three doses or more, weekly or daily | During pregnancy (no specification) |
DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; IU, international units; IUGR, intrauterine growth restriction; LBW, low birth weight; MMN, multiple micronutrients; NA, not available; PTB, preterm birth; RAD, recommended dietary allowance; SGA, small-for-gestational age; UNIMMAP, United Nations Multiple Micronutrient Antenatal Preparation.