Low birth weight
Supplements studied for low birth weight.
Overview
Evidence for preventing low birth weight is mixed and mostly limited across 31 studies. Maternal Iron supplementation during pregnancy shows early but uncertain associations across the birth-weight distribution. Calcium supplements of 1000 to 2000 mg daily during pregnancy did not reduce low birth weight risk in pooled analyses.
Casein Protein formulas support growth comparably to breast milk or other formulas over six weeks to six months, though whey may help premature babies more. L-Carnitine and Vitamin D show mixed or unclear results for birth weight specifically. See the heatmap and evidence reviews below for details.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Vitamin D | ★★★★★ | Low |
| Vitamin B9 (Folate) | ★★★★★ | Low |
| Saccharomyces boulardii | ★★★★★ | Low |
| L-Carnitine | ★★★★★ | Very Low / None |
| Iron | ★★★★★ | Low |
| Casein Protein | ★★★★★ | Very Low / None |
| Calcium | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
7 supplements for and rated at least stars. All purchase bands. No minimum star filter.
Vitamin B9 (Folate)View supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is not clear if taking folic acid during pregnancy reduces the chance of having a baby with low birth weight.
- Some studies show that taking folic acid supplements during pregnancy can increase average birth weight.
- Taking folic acid before or around the time of conception may lower the risk of having a small baby for their gestational age, but starting folic acid after pregnancy begins might not have this effect.
- A study in pregnant women in China found that taking folic acid before and during pregnancy or during pregnancy for at least 12 weeks lowered the chance of low birth weight by about 20%.
- Eating foods high in folate did not show the same benefit.
- Other studies found no clear link between folic acid use in pregnancy and low birth weight.
- The timing and amount of folic acid taken may be important for these effects.
Browse 5 studies·2 meta-analyses
ObservationalFolic Acid and Risk of Preterm Birth, Preeclampsia, and Fetal Growth Restriction Among Women With Epilepsy: A Prospective Cohort Study2022n=64
An observational study of 64 women found that aSM-treated women with epilepsy starting folic acid after the first trimester had a higher risk compared with women without epilepsy with similar timing of folic acid (aOR 2.6, 95% CI 1.1-6.5), and even higher if not using folic acid (aOR 9.4, 95% CI 2.6-34.8).
- Effect
- No Benefit
- Duration
- 4 weeks before pregnancy to 12 weeks gestation
- Population
- Women
- Participants
- 64
ObservationalMaternal Folic Acid Supplementation, Dietary Folate Intake, and Low Birth Weight: A Birth Cohort Study2022n=10,542
An observational study of 10542 women found that compared with non-users, folic acid supplementation was associated with a reduced risk of LBW ( OR : 0.80, 95% CI : 0.66-0.97), and the reduced risk was mainly seen for term-LBW ( OR : 0.59, 95% CI : 0.41-0.85), and multiparous-LBW ( OR : 0.72, 95% CI : 0.54-0.94).
- Effect
- Benefit
- Dose
- 2010–2012 g/day
- Population
- Women
- Participants
- 10,542
ObservationalMaternal folic acid supplementation and more prominent birth weight gain in twin birth compared with singleton birth: a cross-sectional study in northwest China2020
An observational study in women found that 4 mg/day the present study suggests the association of periconceptional 0·4 mg/d FA supplementation with increased birth weight and reduced risk of SGA and LBW in both singletons and twins, and this association may be more prominent in twins.
- Effect
- Benefit
- Dose
- 4 mg/day
- Population
- Women
MetaEffectiveness of folic acid supplementation in pregnancy on reducing the risk of small-for-gestational age neonates: a population study, systematic review and meta-analysis2015
A meta-analysis found that preconception commencement of FA supplementation was associated with reduced risk of SGA <10th centile (aOR 0.80, 95% CI 0.71-0.90, P < 0.01) and SGA <5th centile (aOR 0.78, 95% CI 0.66-0.91, P < 0.01).
- Effect
- Benefit
- Population
- Pregnant women
MetaFolic acid supplementation during pregnancy for maternal health and pregnancy outcomes2013n=17,771
A meta-analysis of 17771 participants found that this review found that folic acid supplementation has no impact on pregnancy outcomes such as preterm birth (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.73 to 1.38; three studies, 2959 participants), and stillbirths/neonatal deaths (RR 1.33, 95% CI 0.96 to 1.85;.
- Effect
- No Benefit
- Population
- Women
- Participants
- 17,771
Vitamin DView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is unclear whether taking vitamin D during pregnancy helps prevent having a low birth weight baby.
- Studies show that very low vitamin D levels in pregnant women are linked to smaller babies and higher chances of low birth weight.
Browse 6 studies·4 meta-analyses
MetaVitamin D supplementation for women during pregnancy2024n=1,368
An updated Cochrane review of 10 RCTs (2,313 pregnant women) found vitamin D alone may reduce severe postpartum hemorrhage and low birthweight, but evidence was low to very low certainty.
- Effect
- Benefit
- Population
- Women
- Participants
- 1,368
MetaEffects of vitamin D supplementation during pregnancy on offspring health at birth: A meta-analysis of randomized controlled trails2022n=11,082
A meta-analysis of 42 pregnancy RCTs (11,082 participants) found vitamin D supplementation reduced intrauterine or neonatal death (RR 0.69) and increased birth length but not birth weight.
- Effect
- Benefit
- Dose
- 400 IU/day
- Population
- Pregnant women
- Participants
- 11,082
MetaVitamin D status during pregnancy and offspring outcomes: a systematic review and meta-analysis of observational studies2020
A meta-analysis of 54 observational studies found maternal vitamin D deficiency below 30 nmol/L was linked to lower birthweight, higher preterm birth risk (OR 1.59), and adverse neurodevelopmental scores.
- Effect
- Benefit
- Dose
- 87.82 g/day
- Population
- Pregnant women
MetaEffects of Vitamin D Supplementation During Pregnancy on Birth Size: A Systematic Review and Meta-Analysis of Randomized Controlled Trials2019
A meta-analysis of 13 pregnancy RCTs found vitamin D supplementation increased birthweight by 103 g, reduced low birthweight (RR 0.40), and lowered small-for-gestational-age risk (RR 0.69).
- Effect
- Benefit
- Dose
- 103.17 g/day
- Population
- Pregnant women
MetaVitamin D supplementation during pregnancy: state of the evidence from a systematic review of randomised trials2017n=8,406
A systematic review of 43 prenatal vitamin D RCTs (8,406 participants) found supplementation increased birth weight and reduced wheeze by age 3 but showed limited maternal clinical benefit.
- Effect
- Benefit
- Dose
- 600 IU/day
- Population
- Pregnant women
- Participants
- 8,406
MetaVitamin D during pregnancy and maternal, neonatal and infant health outcomes: a systematic review and meta-analysis2012
A review of 5 small pregnancy vitamin D RCTs found supplementation may reduce low birthweight (RR 0.40) but evidence for other perinatal outcomes was limited.
- Effect
- Benefit
- Population
- Pregnant women
Saccharomyces boulardiiView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is uncertain if taking Saccharomyces boulardii by mouth helps low birth weight babies grow better.
- Early research in premature low birth weight infants showed that giving a specific S. boulardii supplement with formula for 1 to 4 weeks helped babies gain more weight and improved how well they tolerated feeding compared to formula alone.
Browse 1 study
RCTA double-blinded randomized trial on growth and feeding tolerance with Saccharomyces boulardii CNCM I-745 in formula-fed preterm infants2016
In preterm neonates 30–37 weeks, S. boulardii 50 mg/kg twice daily increased weight gain (16.1 vs 10.7 g/kg/day) versus control.
- Effect
- Benefit
- Duration
- 30–37 weeks
- Dose
- 50 mg/kg
- Population
- Infants
- Ages
- 30–37 weeks
Casein ProteinView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Research shows that casein-based infant formulas, when given for 6 weeks to 6 months, generally support growth in babies just as well as breast milk or other types of formulas, including whey-based, rice-based, cow’s milk, or amino acid formulas.
- However, some studies suggest that for premature or very small babies, whey-based formulas may help growth better than casein-based formulas.
Browse 7 studies
RCTAre babies more satisfied by casein based formulas?1989n=173
An RCT of 173 infants found ~23% had formula changed by 6 weeks regardless of starting whey- or casein-dominant formula, arguing against inherent satiety differences.
- Effect
- No Benefit
- Duration
- 6 weeks
- Population
- Infants
- Participants
- 173
RCTGrowth and metabolic response of premature infants fed whey- or casein-dominant formulas after hospital discharge1989
In 19 preterm infants followed 6 months after discharge, whey- vs casein-dominant formula produced no significant differences in growth or biochemistry.
- Effect
- No Benefit
- Duration
- 6 months
- Population
- Infants
RCTLate metabolic acidosis and poor weight gain in moderately pre-term babies fed with a casein-predominant formula: a continuing need for caution1989
In 70 moderately preterm Chinese infants, casein-predominant formula caused persistent metabolic acidosis and poorer weight gain vs humanized or special preterm formulas.
- Effect
- No Benefit
- Duration
- 32–35 weeks
- Population
- Infants
RCTGrowth and adiposity of term infants fed whey-predominant or casein-predominant formulas or human milk1987n=111
In 111 term infants, whey- or casein-predominant formula and breast milk led to similar growth and body composition over 16 weeks.
- Effect
- No Benefit
- Duration
- 16 weeks
- Population
- Term infants
- Participants
- 111
- Ages
- 0–16 weeks
RCTProtein quality in feeding low birth weight infants: a comparison of whey-predominant versus casein-predominant formulas1987n=30
In 30 low-birth-weight infants, whey- vs casein-predominant formula at ~3.4 g/kg/day protein produced similar growth, nitrogen retention, and tolerance over feeding.
- Effect
- No Benefit
- Dose
- 3.4 g/kg
- Population
- Low birth weight infants
- Participants
- 30
Controlled trialA comparative trial of casein or whey-predominant formulae in healthy infants1986n=100
In 100 healthy infants over 6 weeks, whey-predominant formula produced greater weight gain and head growth than casein-predominant Vitamilk.
- Effect
- No Benefit
- Duration
- 6 weeks
- Population
- Infants
- Participants
- 100
RCTComparative growth and biochemical response of very low birthweight infants fed own mother's milk, a premature infant formula, or one of two standard formulas1985n=30
In VLBW infants, premature formula supported faster growth than standard or mother's milk alone; mother's milk groups had lower phosphate and higher alkaline phosphatase.
- Effect
- No Benefit
- Dose
- 28.0 g/day
- Population
- Very low birth weight infants
- Participants
- 30
IronView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Early research on low birth weight is limited.
- A quantile regression analysis investigating how maternal iron supplementation during pregnancy relates to newborn birth weight across different points of the birth-weight distribution.
- More studies are needed before any benefit can be considered reliable.
Browse 1 study
ObservationalAssociation between maternal iron supplementation and newborn birth weight: a quantile regression analysis2021n=28,209
In 28,209 Chinese mother-infant pairs, maternal iron supplementation during pregnancy was associated with higher newborn birth weight, especially among anemic mothers and lower birth-weight percentiles.
- Effect
- Benefit
- Population
- Women
- Participants
- 28,209
L-CarnitineView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Several small studies in premature babies who receive nutrition through their veins show that giving L-carnitine by mouth or injection may help improve fat use and weight gain.
- However, other small studies did not find a clear increase in weight.
- Because these studies were very small, the results are mixed and not certain whether L-carnitine helps babies grow better.
Browse 10 studies
RCTL-carnitine-supplemented parenteral nutrition improves fat metabolism but fails to support compensatory growth in premature Korean infants2010n=13
In 13 neonates, L-carnitine-supplemented parenteral nutrition improved fat metabolism markers but did not improve weight gain versus standard PN.
- Effect
- No Benefit
- Dose
- 10 mg/kg/day
- Population
- Pregnant women
- Participants
- 13
RCTLack of effect of L-carnitine supplementation on weight gain in very preterm infants2005n=63
In 63 very preterm infants, L-carnitine 16 mL/day did not improve weight gain versus control despite low carnitine status at enrollment.
- Effect
- No Benefit
- Dose
- 16 mL/day
- Population
- Infants
- Participants
- 63
- Ages
- <29 weeks gestation
Primary and secondary alterations of neonatal carnitine metabolism1999
A review describes primary and secondary neonatal carnitine metabolism disorders and the role of carnitine in fatty acid oxidation and coenzyme A homeostasis.
- Population
- Adults
RCTRandomised controlled trial of L-carnitine as a nutritional supplement in preterm infants1998
In preterm infants, L-carnitine 25 mg/kg/day did not significantly improve growth or reduce hypoglycemia versus control in a randomized trial.
- Effect
- No Benefit
- Dose
- 25 mg/kg/day
- Population
- Infants
- Ages
- 28–34 weeks gestation
RCTEffects of parenteral L-carnitine supplementation on fat metabolism and nutrition in premature neonates1995
In 43 very low birth weight infants, parenteral L-carnitine improved fat metabolism and carnitine concentrations but did not clearly improve nutritional outcomes versus control.
- Effect
- Benefit
- Dose
- 1500 g/day
- Population
- Infants
Carnitine and total parenteral nutrition of the neonate1990
A review discusses carnitine requirements during neonatal total parenteral nutrition and the role of carnitine in newborn fat metabolism.
- Population
- Infants
RCTEffect of intravenous L-carnitine on growth parameters and fat metabolism during parenteral nutrition in neonates1990n=23
In 23 neonates on parenteral nutrition, IV L-carnitine 0.5 g/kg improved fatty acid oxidation markers but did not significantly improve growth versus control.
- Effect
- Benefit
- Duration
- 14 days
- Dose
- 0.5 g/kg
- Population
- Infants
- Participants
- 23
RCTOral L-carnitine supplementation in low-birth-weight newborns: a study on neonates requiring combined parenteral and enteral nutrition1986
In 10 premature infants, oral L-carnitine supplementation altered plasma ketone bodies and triglycerides during combined enteral and parenteral feeding versus control.
- Effect
- Benefit
- Duration
- 9–14 days
- Population
- Infants
An evaluation of orally supplemented L-carnitine in premature infants receiving Intralipid 20%1983
In premature infants receiving Intralipid, oral L-carnitine did not clearly prevent carnitine deficiency or improve lipid tolerance versus unsupplemented control.
- Effect
- No Benefit
RCTCarnitine deficiency in premature infants receiving total parenteral nutrition: effect of L-carnitine supplementation1983
In premature infants on total parenteral nutrition, carnitine 10 mg/kg did not significantly improve fat tolerance or correct carnitine deficiency versus control in a randomized trial.
- Effect
- No Benefit
- Duration
- 29–33 weeks
- Dose
- 10 mg/kg
- Population
- Infants
- Ages
- 6–10 days
CalciumView supplement →
Do not purchase·★★★★★
How we scored this▸
- It is not clear whether taking calcium supplements during pregnancy helps prevent babies from being born with low birth weight.
- Research combining several studies found that calcium supplements in amounts of 1000 to 2000 mg per day did not lower the risk of low birth weight compared with women who took no supplements or a placebo.
Browse 1 study
MetaCalcium supplementation (other than for preventing or treating hypertension) for improving pregnancy and infant outcomes2015n=18,587
A Cochrane systematic review of 23 randomized controlled trials (17,842 women) assessing calcium supplementation in pregnancy for outcomes other than hypertension or preeclampsia. The review found no significant reduction in preterm birth or low birth weight, though a small increase in mean birth weight (~56 g) was observed.
- Effect
- No Benefit
- Population
- Women
- Participants
- 18,587
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| L-Carnitine | ★★★★★40% | 10 | 0 | 32% |
| Casein Protein | ★★★★★40% | 7 | 0 | 23% |
| Vitamin D | ★★★★★52% | 6 | 4 | 19% |
| Vitamin B9 (Folate) | ★★★★★52% | 5 | 2 | 16% |
| Calcium | ★★★★★36% | 1 | 0 | 3% |
| Iron | ★★★★★40% | 1 | 0 | 3% |
| Saccharomyces boulardii | ★★★★★44% | 1 | 0 | 3% |