Pregnancy health
Supplements studied for pregnancy health.
Overview
Iron has the most studies (16) among supplements tracked for general pregnancy health, but current evidence is limited and more research is needed before any reliable benefit can be concluded. Probiotics (2 studies) and Vitamin D (2 studies) are rated as possibly effective, though the underlying trial data remain modest.
Selenium (2 studies) has insufficient evidence, and iodine (1 study) lacks enough data to determine benefit. Overall, supplement evidence for broad pregnancy health outcomes is still developing. The heatmap and evidence reviews below provide supplement-level detail.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Iron | ★★★★★ | Medium |
| Vitamin D | ★★★★★ | Medium |
| Probiotics | ★★★★★ | Medium |
| Iodine | ★★★★★ | Low |
| Selenium | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
5 supplements for , and rated at least stars. All purchase bands. No minimum star filter.
IronView supplement →
Consider purchase·★★★★★
How we scored this▸
- Early research on pregnancy health is limited.
- A systematic review and meta-analysis assessing both beneficial and adverse effects of oral iron supplementation in non-anaemic pregnant women.
- More studies are needed before any benefit can be considered reliable.
Browse 16 studies·10 meta-analyses
MetaIntermittent versus daily oral iron folic acid supplementation and pregnancy outcome in low- and middle-income countries: a systematic review and meta-analysis of experimental studies2025
A meta-analysis of 22 trials comparing intermittent versus daily iron-folic acid in pregnancy found similar anemia incidence but lower gastric side effects and better adherence with intermittent dosing.
- Population
- Women
MetaThe benefits and harms of oral iron supplementation in non-anaemic pregnant women: a systematic review and meta-analysis2025n=10
A meta-analysis of 23 trials (4,492 nonanemic pregnant women) found prophylactic oral iron reduced anemia risk (NNT 10) and raised hemoglobin and ferritin without clear effects on birth weight or preterm birth.
- Effect
- Benefit
- Population
- Women
- Participants
- 10
MetaClinical outcome post treatment of anemia in pregnancy with intravenous versus oral iron therapy: a systematic review and meta-analysis2024n=13,909
A meta-analysis of 34 pregnancy trials (13,909 women) found IV iron raised hemoglobin faster, reduced maternal adverse events (OR 0.39 vs oral iron), but neonatal outcomes did not differ significantly.
- Effect
- Benefit
- Population
- Women
- Participants
- 13,909
Systematic reviewEffect and safety of intravenous iron compared to oral iron for treatment of iron deficiency anaemia in pregnancy2024n=3,939
A Cochrane review of 13 RCTs (3,939 pregnant women with anemia) found IV iron likely increased antenatal and postpartum hemoglobin and reduced anemia versus oral iron, with uncertain effects on postpartum hemorrhage.
- Effect
- Benefit
- Duration
- 13–37 weeks
- Population
- Women
- Participants
- 3,939
MetaEfficacy of daily versus intermittent oral iron supplementation for prevention of anaemia among pregnant women: a systematic review and meta-analysis2024n=4,365
A meta-analysis of 26 RCTs (4,365 pregnant women) found intermittent oral iron (~120 mg/day) raised hemoglobin similarly to daily 60 mg iron but caused less nausea, diarrhea, and constipation.
- Dose
- 120 mg/day
- Population
- Women
- Participants
- 4,365
MetaEfficacy of intravenous iron supplementation in reducing transfusion risk following cardiac surgery: an updated meta-analysis of randomised controlled trials2024n=1,989
An updated meta-analysis of 14 cardiac surgery RCTs (1,955 patients) found perioperative IV iron reduced red blood cell transfusion risk (RR 0.77) and improved postoperative hemoglobin and iron status.
- Effect
- Benefit
- Dose
- 0.17 g/day
- Population
- Adults
- Participants
- 1,989
MetaIron supplements in pregnant women with normal iron status: A systematic review and meta-analysis2023n=2,822
A meta-analysis of 8 RCTs (2,822 iron-replete nonanemic pregnant women) found daily oral iron probably reduced iron-deficiency anemia at term (RR 0.51) and low birthweight (RR 0.30).
- Effect
- Benefit
- Dose
- 130 g/day
- Population
- Women
- Participants
- 2,822
RCTIron supplementation in pregnant Danish women revisited: Effects on prepartum and postpartum iron deficiency, anemia, serum erythropoietin; including iron status, erythropoietin and anthropometrics in newborns. A randomized, placebo-controlled study2022n=119
In 119 Danish pregnant women, ferrous fumarate 66 mg/day from mid-pregnancy through 8 weeks postpartum reduced iron deficiency and anemia versus placebo and improved newborn cord ferritin.
- Effect
- Benefit
- Duration
- 24–27 weeks
- Dose
- 66 mg/day
- Population
- Women
- Participants
- 119
RCTA randomized controlled trial comparing the efficacy, tolerability, and cost of oral iron preparations in iron-deficiency anemia in pregnancy2021n=30
In 120 pregnant women with iron-deficiency anemia, ferrous sulfate, fumarate, ascorbate, and carbonyl iron at 200 mg/day elemental iron were equally effective for correcting anemia over the study period.
- Effect
- Benefit
- Dose
- 200 mg/day
- Population
- Women
- Participants
- 30
MetaIron preparations for women of reproductive age with iron deficiency anaemia in pregnancy (FRIDA): a systematic review and network meta-analysis2021n=9,145
A network meta-analysis of 53 pregnancy trials (9,145 women) found IV iron sucrose and ferric carboxymaltose improved hemoglobin and ferritin more than oral ferrous sulfate for iron-deficiency anemia.
- Effect
- Benefit
- Dose
- 60 mg/day
- Population
- Women
- Participants
- 9,145
Systematic reviewComparison of different doses of daily iron supplementation for anemia prophylaxis in pregnancy: A systematic review2020
A systematic review of 11 pregnancy iron prophylaxis trials found 30 mg/day maintained hemoglobin in global studies, while Indian data showed inconsistent results between 60 and 120 mg/day doses.
- Dose
- 30 mg/day
- Population
- Women
Systematic reviewEfficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials2018n=1,170
A systematic review and meta-analysis of 1,170 non-anaemic iron-deficient adults found iron therapy may reduce fatigue, though benefits on physical capacity were inconsistent across trials.
- Effect
- Benefit
- Dose
- 4.01 g/day
- Population
- Adults
- Participants
- 1,170
MetaIntermittent oral iron supplementation during pregnancy2015n=5,490
A Cochrane meta-analysis of 21 pregnancy trials (5,490 women) found intermittent versus daily iron caused fewer side effects and less high hemoglobin, with similar effects on maternal anemia and infant outcomes.
- Population
- Women
- Participants
- 5,490
MetaEffects and safety of preventive oral iron or iron+folic acid supplementation for women during pregnancy2009
A Cochrane review of 49 pregnancy trials found daily or intermittent iron with or without folic acid prevented anemia and iron deficiency but did not clearly reduce low birthweight, preterm birth, or postpartum hemorrhage.
- Effect
- Benefit
- Population
- Women
MetaTreatments for iron-deficiency anaemia in pregnancy2007n=2,578
A Cochrane review of 17 pregnancy anemia trials (2,578 women) found oral iron improved hematologic indices with frequent GI adverse effects; parenteral iron improved hematology but lacked robust clinical outcome data.
- Effect
- Benefit
- Dose
- 11 g/day
- Population
- Women
- Participants
- 2,578
MetaEffects of iron supplementation on maternal hematologic status in pregnancy2002
A meta-analysis of prenatal iron trials in developing countries found iron supplementation raises maternal hemoglobin in a dose- and baseline-dependent manner, though clinical benefits remain uncertain.
- Effect
- Benefit
- Population
- Women
ProbioticsView supplement →
Consider purchase·★★★★★
How we scored this▸
- Probiotics are possibly effective for Pregnancy health.
Browse 2 studies·1 meta-analysis
RCTEfficacy of Oral Probiotic Supplementation in Preventing Vulvovaginal Infections During Pregnancy: A Randomized and Placebo-Controlled Clinical Trial2024
In 100 pregnant women, oral multi-strain probiotics until delivery did not reduce vulvovaginal infection rate versus placebo (29% vs 27%, p=0.80).
- Effect
- No Benefit
- Population
- Women
- Ages
- 18+
MetaProbiotics for the prevention of gestational diabetes mellitus: A meta-analysis of randomized controlled trials2024n=3,527
A meta-analysis of 14 pregnancy RCTs (n=3527) found probiotics reduced gestational diabetes incidence (RR 0.71) mainly in women with BMI <26 kg/m² and age <30 years.
- Effect
- Benefit
- Population
- Women
- Participants
- 3,527
Vitamin DView supplement →
Consider purchase·★★★★★
How we scored this▸
- Vitamin D is possibly effective for Pregnancy health.
Browse 2 studies·1 meta-analysis
MetaEfficacy of vitamin D supplementation on the incidence of preeclampsia: a systematic review and meta-analysis2024n=10,613
A meta-analysis of RCTs in 10,613 pregnant women found vitamin D supplementation did not significantly reduce preeclampsia incidence versus control.
- Effect
- No Benefit
- Population
- Women
- Participants
- 10,613
RCTReduced primary care respiratory infection visits following pregnancy and infancy vitamin D supplementation: a randomised controlled trial2015n=87
In a New Zealand RCT of 260 mother-infant pairs given up to 2000/800 IU/day vitamin D, the higher-dose group had fewer primary care respiratory infection visits by age 18 months.
- Effect
- Benefit
- Duration
- 6–18 months
- Dose
- 800 IU/day
- Population
- Women
- Participants
- 87
- Ages
- 6–18
IodineView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- There is not enough evidence to know whether iodine helps with pregnancy health.
Browse 1 study·1 meta-analysis
MetaSystematic review and meta-analysis of the effects of iodine supplementation on thyroid function and child neurodevelopment in mildly-to-moderately iodine-deficient pregnant women2020
A meta-analysis of trials in mildly to moderately iodine-deficient pregnant women found insufficient consistent evidence that iodine supplementation clearly improves maternal thyroid function or child neurodevelopment.
- Effect
- Benefit
- Dose
- 50–149 mcg/day
- Population
- Women
SeleniumView supplement →
Do not purchase·★★★★★
How we scored this▸
- Selenium has insufficient evidence for Pregnancy health.
Browse 2 studies
RCTEffect of selenium on markers of risk of pre-eclampsia in UK pregnant women: a randomised, controlled pilot trial2014
In 230 UK pregnant women, selenium 60 mcg/day from weeks 12–14 to delivery did not reduce preeclampsia or oxidative stress markers versus placebo.
- Effect
- No Benefit
- Duration
- 12–14 weeks
- Dose
- 60 mcg/day
- Population
- Women
RCTSelenium supplementation and the incidence of preeclampsia in pregnant Iranian women: a randomized, double-blind, placebo-controlled pilot trial2010n=83
In 60 high-risk Iranian pregnant women, selenium 100 mcg/day for 6 months did not prevent preeclampsia versus placebo.
- Effect
- No Benefit
- Duration
- 6 months
- Dose
- 100 mcg/day
- Population
- Women
- Participants
- 83
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Iron | ★★★★★68% | 16 | 10 | 70% |
| Probiotics | ★★★★★64% | 2 | 1 | 9% |
| Selenium | ★★★★★32% | 2 | 0 | 9% |
| Vitamin D | ★★★★★64% | 2 | 1 | 9% |
| Iodine | ★★★★★48% | 1 | 1 | 4% |