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Is protein safe during pregnancy?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

A Cochrane review found that its one trial of a high-protein supplement (505 women) linked it to more small-for-gestational-age babies, and its authors said high-protein supplements may be harmful to the fetus. NIH advises caution with high protein intakes from supplements. Ask your doctor before using protein powder while pregnant.1,2

Key facts

  • In the Cochrane review, one trial of high-protein supplementation (505 women) linked it to more small-for-gestational-age babies (risk ratio 1.58, range 1.03 to 2.41).1
  • The same review linked balanced energy and protein supplements, a different design, to fewer small-for-gestational-age babies and a lower stillbirth risk.1
  • NIH sets no upper limit for protein, but advises caution with high intakes from foods and supplements combined because data are limited.2
  • NIH advises being cautious with supplements beyond a standard prenatal supplement in pregnancy, because many have not been well tested in pregnant women.3
  • FDA's interim reference level for lead from all food is 8.8 micrograms a day for women of childbearing age.4

What a Cochrane review found about protein supplements in pregnancy

The main systematic evidence is a Cochrane review of 17 randomized trials with 9030 women that tested advice or supplements meant to raise energy and protein intake during pregnancy. It sorted the supplement trials by design, and the designs gave different results.1

Cochrane review results by type of protein supplement in pregnancy1
Supplement designWhat the review found
Balanced energy and protein (12 trials, 6705 women)Fewer small-for-gestational-age babies (risk ratio 0.79) and a lower stillbirth risk (0.60); no clear effect on preterm birth
High protein (1 trial, 505 women)More small-for-gestational-age babies (risk ratio 1.58, range 1.03 to 2.41); no clear effect on stillbirth, preterm birth or birth weight
Protein alone at the same calories (2 trials, 184 women)No clear effect on birth weight or weight gain; very low quality evidence

The authors concluded that balanced energy and protein supplements seem to aid fetal growth, while high-protein supplementation does not seem to be beneficial and may be harmful to the fetus. They also said the results should be read with caution, because the risk of bias was unclear or high in several trials and the quality of evidence was low for important outcomes. The abstract does not describe the products, so it cannot be applied to a particular powder.1

What NIH says about protein amounts

No tolerable upper intake level has been set for protein, because the risk of harm from protein in food is very low. NIH still advises caution with high intakes from foods and supplements combined, since data are limited, and reports no safety concerns up to about 2.0 g per kg a day.2

The sources checked give no pregnancy-specific amount for protein supplements. MedlinePlus says protein should supply 10 to 35 percent of daily calories for healthy adults, and NIH's recommended amount for adults is 0.8 g per kg of body weight a day. Both are about food and overall diet, not powders.2,5

Lead and other metals in some powders

Protein powders are made from milk, eggs or plants, and plants can take up lead from the soil. FDA sets interim reference levels for lead from all food, including one for women of childbearing age.2,4

Plants can take up lead from the environment. In a 2026 study of 30 protein supplements, plant-based products averaged about three times the lead of dairy-based ones (0.18 against 0.06 mg per kg).4,6

FDA's interim reference levels for lead from all food are 2.2 micrograms a day for children and 8.8 micrograms a day for women of childbearing age.4

A 2020 risk assessment based on published tests estimated that one to three servings of protein powder a day would not raise health risks from arsenic, cadmium, mercury or lead.7

Who should ask their doctor

Ask your doctor, midwife or a dietitian before using protein powder in pregnancy. Do so especially if you have kidney disease or were told to limit protein, if you are allergic to milk, soy, peanuts or legumes, or if the powder is a blend with other ingredients. An international expert group says people with severely reduced kidney function may need to limit protein, and FDA names milk, soy and peanuts as major food allergens.8,9

Questions people ask

Is protein okay during pregnancy?

Protein from food is part of ordinary diets, and MedlinePlus gives 10 to 35 percent of calories as the range for healthy adults. The Cochrane findings above are about supplements, so ask your doctor about both.1,5

Is protein powder safe during pregnancy?

The sources checked report no trial of modern protein powders in pregnancy. The Cochrane review links one high-protein supplement trial to more small babies, and NIH advises caution with high intakes from supplements.1,2

Is whey protein safe during pregnancy?

None of the sources checked tests whey protein in pregnancy. A 2021 systematic review of whey and adverse effects covers long-term, excessive use, and its abstract does not mention pregnancy, so ask your doctor.10

Is a ready-to-drink protein shake safe during pregnancy?

This page does not review specific brands or products. Protein shakes vary in protein, calories and other ingredients, so take the label to your doctor or dietitian.1

Is pea protein safe during pregnancy?

The sources checked do not test pea protein in pregnancy. A 2026 study found plant-based protein supplements averaged about three times the lead of dairy-based ones (0.18 against 0.06 mg per kg), a point worth raising with your doctor.4,6

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Sources

  1. Ota E, Hori H, Mori R, Tobe-Gai R, Farrar D. Antenatal dietary education and supplementation to increase energy and protein intake. Cochrane Database Syst Rev (systematic review of randomized trials). 2015;(6):CD000032. Opened 2026-10-11.
  2. National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Health Professionals. Updated April 1, 2024. Opened 2026-10-07.
  3. National Institutes of Health, Office of Dietary Supplements. Dietary Supplements: What You Need To Know. Fact sheet for consumers. Updated January 4, 2023. Opened 2026-10-07.
  4. U.S. Food and Drug Administration. Lead in Food and Foodwares. Content current as of January 6, 2025. Opened 2026-10-07.
  5. MedlinePlus Medical Encyclopedia. Protein in diet. U.S. National Library of Medicine. Reviewed April 1, 2025. Opened 2026-10-07.
  6. Chen M, Dong R, Lai W. Heavy metal and microplastic exposure from sports protein supplements: Integrated health risk modeling and scenario analysis. Environ Res. 2026;295:123988. Opened 2026-10-07.
  7. Bandara SB, Towle KM, Monnot AD. A human health risk assessment of heavy metal ingestion among consumers of protein powder supplements. Toxicol Rep. 2020;7:1255-1262. Opened 2026-10-07.
  8. Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542-559. Opened 2026-10-07.
  9. U.S. Food and Drug Administration. Food Allergies. Content current as of March 11, 2026. Opened 2026-10-07.
  10. Vasconcelos QDJS, Bachur TPR, Aragao GF. Whey protein supplementation and its potentially adverse effects on health: a systematic review. Appl Physiol Nutr Metab. 2021;46(1):27-33. Opened 2026-10-11.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.