Condition
Low Birth Weight
Low birth weight means a baby is born smaller than the healthy range, often because of limited nourishment before birth, which raises the odds of later health problems. Prenatal multivitamins, iron and folic acid have the strongest evidence overall, yet for birth weight itself, iron studies found a change without a clear direction and folic acid results were mixed. Zinc showed no clear difference, and the iron findings came from one small review.
Sources: PMID 37403900; PMID 22992251
- Supplements studied
- 4
- Graded outcomes
- 4
- People studied
- 19,281
Evidence by supplement
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Infant Birth Weight Mixed effect | 2 studies | 707 people | ||||
Studies that measured infant birth weight | ||||||
| Infant Death Risk | Improves (the measure goes down) | 4,002 people | ||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Infant Birth Weight Small Increase | Improves (the measure goes down) | Small effect | 1 study | 361 people | ||
Studies that measured infant birth weight | ||||||
| Iron Deficiency Anemia Risk | Changes; see studies | 1,670 people | ||||
| Iron Deficiency Risk | Changes; see studies | 1,663 people | ||||
Fish Oil
- Infant Birth Weight: improves
- Pre-Eclampsia Risk: changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Infant Birth Weight Small Increase | Improves (the measure goes down) | Small effect | 2,302 people | |||
| Pre-Eclampsia Risk | Changes; see studies | 1 study | 1,831 people | |||
Studies that measured pre-eclampsia risk | ||||||
Zinc
- Infant Birth Weight
- Preterm Birth Risk: changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Infant Birth Weight No effect | NoneNo effect | 6,757 people | ||||
| Preterm Birth Risk | Changes; see studies | 1 study | 7,637 people | |||
Studies that measured preterm birth risk | ||||||
Key findings
- Infant Birth Weight
The Low Birth Weight Prevention (Prenatal Nutrition) protocol
2 primary supplements · 5 supporting supplements
- Prenatal MultivitaminOne prenatal multivitamin daily throughout pregnancy
- Iron27–60 mg daily (higher if anemic)
Studies cited
5 studies from PubMed
- Zinc supplementation for improving pregnancy and infant outcome.
- Iron supplements in pregnant women with normal iron status: A systematic review and meta-analysis.
- Folic acid supplementation in pregnancy to prevent preterm birth: a systematic review and meta-analysis of randomized controlled trials.
- Effect of folate intake on health outcomes in pregnancy: a systematic review and meta-analysis on birth weight, placental weight and length of gestation.
- Marine oil, and other prostaglandin precursor, supplementation for pregnancy uncomplicated by pre-eclampsia or intrauterine growth restriction