Is protein powder safe during pregnancy?

Nobody knows, because no trial or cohort has tested commercial protein powder or shakes in pregnant women. What has been tested is protein given as food-based supplements, and the answer splits in two. Balanced supplements, where protein is a modest share of the calories, cut stillbirth risk by 40 per cent in a Cochrane analysis of five trials in 3,408 women, mostly in low-income settings. A high-protein supplement in one trial of 505 women raised the risk of a baby small for its gestational age by 58 per cent, and WHO does not recommend high-protein supplements for pregnant women in undernourished populations.

Unsettled. The powder itself is untested in pregnancy. Every number on this page comes from food-based supplements given in trials, from diets observed in ordinary life, or from lab tests of the products. None of them answers the question for a well-fed woman adding a scoop to her day.

Risk ratios against comparison groups

Balanced energy and protein, trialsHigh-protein, one trialObservational data

Left of 1.0 is lower risk, right is higher. The first three rows are randomized trials of food-based supplements, not powders. The last two are diets observed in ordinary life and cannot show cause. The abstracts do not give the baseline rates, so these ratios cannot be turned into cases per 1,000 women. Sources: cards ev-ppreg-01, 02, 04, 07 and 08 below.

What the trials found

Balanced supplements in women who were short of food

The Cochrane review pooled trials of balanced energy and protein supplements, mostly in low-income settings. Stillbirth fell with a risk ratio of 0.60, with a confidence interval from 0.39 to 0.94, across five trials in 3,408 women. Mean birthweight rose by 41 g across 11 trials in 5,385 women, with an interval from 5 to 77 g. Both results were rated moderate quality. The supplements were food-based or fortified foods, and the review rated the overall risk of bias unclear.

Extra grams of birthweight with balanced energy and protein supplements

The one absolute number the reviews report. Both intervals stay above zero. The second review mixes trials with observational studies, which is why it is rated lower. Sources: cards ev-ppreg-01 and ev-ppreg-06 below.

A 2026 analysis of individual data from eight trials in 10,252 women in low- and middle-income countries found the same direction. Babies born both early and small became 31 percent less likely, with a risk ratio of 0.69 and an interval from 0.52 to 0.91. Babies born at term but small became 12 percent less likely. The comparison groups differed between trials, from standard care to iron and folic acid to a multiple micronutrient tablet. An analysis of 11 trials in 12,549 women in the same kind of countries found these supplements added 1.3 lb (0.59 kg) to the weight a woman gained by delivery, with an interval from 0.26 to 2.3 lb (0.12 to 1.05 kg).

A 2023 systematic review of randomized trials reached the plain conclusion for this group. In pregnant women with undernutrition, balanced protein and energy supplements can reduce low birth weight, small babies and stillbirth. The abstract gives no pooled numbers.

Established. In undernourished pregnant women, balanced energy and protein supplements reduce stillbirth and small babies. That rests on meta-analyses of randomized trials. It says nothing about protein powder in women who already eat enough, because those women were not the people studied.

High-protein supplements, the one warning from trials

The same Cochrane review looked separately at supplements built around a lot of protein. Only one trial tested them, in 505 women. The risk of a small-for-gestational-age baby went up, with a risk ratio of 1.58 and an interval from 1.03 to 2.41, on moderate-quality evidence. The reviewers called for large, well-designed trials of extra energy and protein in women whose intake is below recommended levels.

Who should be careful

Not for everyone. A pregnant woman thinking of a high-protein shake is closest to the one trial that found harm. That trial is a single study, and it tested a supplement rather than a modern powder. It is still the only randomized evidence on adding a lot of protein in pregnancy, and it pointed toward smaller babies.

Gestational diabetes, in observational data only. Across 13 observational studies with 31,005 women, those with the highest total protein intake had a risk ratio for gestational diabetes of 1.82 against the lowest, with an interval from 1.42 to 2.33. Animal protein gave 1.79, and plant protein gave 0.98, which is no difference. A 2026 review of 25 prospective studies in 115,496 pregnant women found 1.62 for animal-sourced protein, with an interval from 1.20 to 2.18 and high variation between studies. This was protein from ordinary food, and the design shows an association, not a cause.

Metals in the product. In lab tests of 30 sports protein powders sold in China, every sample held at least one of the metals tested for, and plant-based powders carried 0.18 mg/kg of lead against 0.06 mg/kg in dairy powders. That is product testing, not a study of pregnant women. A European test of 56 plant-based powders found that a 30 g daily serving stayed within reference intake limits for the metals measured, again from product testing with no pregnancy outcomes.

What expert bodies say

WHO, in its 2016 antenatal care guideline: in undernourished populations, high-protein supplementation is not recommended for pregnant women to improve maternal and perinatal outcomes. The recommended daily allowance for protein in pregnancy in the United States is 71 g, which FDA uses as the label reference for pregnant and lactating women. A 2024 AHRQ review puts the same allowance at 1.1 to 1.3 g per kilogram of body weight a day for pregnancy and lactation, higher than for other adults.

Protein needs do go up in pregnancy, and the reference values say by how much. They do not say a powder is the way to reach them, and no trial has tested one in pregnancy. If you doubt that food gets you to 71 g, ask your midwife or doctor, who can look at what you actually eat.

How we searched

Searched: a local copy of the PubMed baseline on 6 October 2026, for protein supplementation, balanced energy protein, protein powder or protein shake with pregnancy (719 hits), for high protein intake with birth weight, fetal growth or gestational diabetes (283), and for protein powder with heavy metals (708, nothing relevant in the top 20). Also Europe PMC titles on protein powder and lead (10), the WHO and agency stores, a local ClinicalTrials.gov snapshot (no relevant trial), and three web searches for the WHO recommendation and newer Cochrane updates.

Included: one Cochrane review, one individual-data meta-analysis and one systematic review of trials, one mixed-design meta-analysis, two meta-analyses of observational studies, two lab surveys of protein powders, and three agency documents. None of the papers was retracted.

Excluded: scoping and umbrella reviews without effect sizes, a cohort meta-analysis that overlaps the two used, older versions of the Cochrane review, Indian product surveys with no pregnancy angle, and consumer group lead tests that are not peer-reviewed sources.

What we read: abstracts for every trial and review, the two lab surveys through Europe PMC, and the relevant sections of the FDA rule and the AHRQ report.

What we could not get: the full text of the WHO guideline (blocked by a captcha, so the wording was confirmed on the WHO eLENA summary and a second guideline register), and the full texts of the Cochrane review and the observational reviews. Listings suggest the Cochrane review has since been split into separate high-protein and balanced-protein reviews, and we could not find them.

What would change this answer

A randomized trial of protein powder in well-nourished pregnant women, with birthweight, small babies and gestational diabetes as outcomes. We found none, finished or running.
The updated Cochrane review of high-protein supplements in pregnancy, if it adds trials to the single one that found harm.
Lab testing of the specific brands sold as pregnancy protein, with lead measured per serving.

More on the product itself: protein supplements. On how much protein people need: the protein guide.

The food behind this question

Protein supplements: the performance gains came with extra calories — numbers, evidence and safety

The same question for other foods (pregnancy)

Sources

ev-ppreg-01 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 3408 (stillbirth); 5385 (birthweight)
Risk of stillbirth was significantly reduced for women given balanced energy and protein supplementation (RR 0.60, 95% CI 0.39 to 0.94, five trials, 3408 women, moderate-quality evidence), and the mean birthweight was significantly increased (random-effects MD +40.96 g, 95% CI 4.66 to 77.26, Tau² = 1744, I² = 44%, 11 trials, 5385 women, moderate-quality evidence).
Who: Pregnant women given balanced energy and protein supplementation, mostly in low-income settings
Effect: stillbirth RR 0.60 (95% CI 0.39 to 0.94), 5 trials, 3408 women; birthweight MD +40.96 g (95% CI 4.66 to 77.26), 11 trials, 5385 women; moderate-quality evidence
Certainty: Supplements were food-based or fortified foods, not commercial protein powders; overall risk of bias unclear.
Cochrane Database Syst Rev, 2015 · checked 2026-10-06 · we read the abstract
ev-ppreg-02 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials, high-protein comparison · n = 505
High-protein supplementation (one trial, 505 women), was associated with a significantly increased risk of small-for-gestational age babies (RR 1.58, 95% CI 1.03 to 2.41, moderate-quality evidence).
Who: Pregnant women given high-protein supplementation, one trial
Effect: small for gestational age RR 1.58 (95% CI 1.03 to 2.41), moderate-quality evidence; no effect on stillbirth, preterm birth or birthweight
Certainty: Single trial of a high-protein supplement, not a commercial protein powder.
Cochrane Database Syst Rev, 2015 · checked 2026-10-06 · we read the abstract
ev-ppreg-03 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 9030
Large, well-designed randomised trials are needed to assess the effects of increasing energy and protein intake during pregnancy in women whose intake is below recommended levels.
Who: Pregnant women in trials of energy and protein supplementation, 17 trials
Effect: call for large randomized trials in women with intake below recommended levels
Certainty: Evidence gap: no trial tested modern powders or shakes, and the review searched to January 2015.
Cochrane Database Syst Rev, 2015 · checked 2026-10-06 · we read the abstract
ev-ppreg-04 · Meta-analysis or systematic review · systematic review and individual participant data meta-analysis of randomized controlled trials · n = 10252
In the four-group categorization, prenatal BEP supplementation led to a 31% lower risk of preterm-SGA (RR: 0.69; 95% CI [0.52, 0.91]; P = 0.008) and a 12% lower risk of term-SGA (RR: 0.88; 95% CI [0.81, 0.96]; P = 0.005).
Who: Pregnant women in low- and middle-income countries, 8 RCTs of prenatal BEP supplements
Effect: preterm-SGA RR 0.69 (95% CI 0.52 to 0.91); term-SGA RR 0.88 (95% CI 0.81 to 0.96)
Certainty: Control arms varied (standard care, iron-folic acid or multiple micronutrients); results apply to undernourished settings.
PLoS Med, 2026 · checked 2026-10-06 · we read the abstract
ev-ppreg-05 · Meta-analysis or systematic review · modular systematic review of randomized controlled trials and reviews of RCTs · n = —
Evidence suggests that balanced protein and energy (BPE) supplementation for pregnant women with undernutrition can reduce the risk of LBW, SGA and SB.
Who: Pregnant women with undernutrition, RCTs and reviews of RCTs
Effect: BPE reduced risk of LBW, SGA and stillbirth in undernourished women (pooled numbers not in the abstract)
Certainty: Benefit is limited to undernourished populations; well-nourished women were not the target.
Am J Clin Nutr, 2023 · checked 2026-10-06 · we read the abstract
ev-ppreg-06 · Observational data · systematic review and meta-analysis of randomized controlled trials and observational studies · n = 24 studies
Meta-analysis of pooled studies revealed that balanced protein supplementation had a significant effect on birthweight (g) (MD: 62.67, CI: 27.92-97.43), low birth weight (LBW) (RR: 0.73, CI: 0.57-0.95), birth length (MD: 0.20, CI: 0.10-0.30), and small-for-gestational-age (SGA) babies (RR: 0.74, CI: 0.59-0.93) and had no significant effect on the birth head circumference (MD: 0.05, CI: -0.09 to 0.20), perinatal death (RR: 0.83, CI: 0.50-1.37), and preterm birth (RR: 0.86, CI: 0.68-1.08).
Who: Pregnant women receiving balanced protein-energy supplementation, 24 studies
Effect: birthweight MD 62.67 g (CI 27.92 to 97.43); LBW RR 0.73 (0.57 to 0.95); SGA RR 0.74 (0.59 to 0.93); preterm birth RR 0.86 (0.68 to 1.08)
Certainty: Pools RCTs with observational studies, so graded C here, not A.
Womens Health (Lond), 2025 · checked 2026-10-06 · we read the abstract
ev-ppreg-07 · Observational data · systematic review and dose-response meta-analysis of observational studies · n = 31005
Comparing the highest and lowest intakes of total, animal, and plant proteins revealed the summary RRs of 1.82 (95% CI: 1.42, 2.33), 1.79 (95% CI: 1.50, 2.14), and 0.98 (95% CI: 0.81, 1.20), respectively, indicating a significant positive association between total and animal protein intake and GDM.
Who: Women before and during pregnancy, 13 observational studies, 3451 GDM cases
Effect: highest vs lowest: total protein RR 1.82 (1.42 to 2.33); animal protein RR 1.79 (1.50 to 2.14); plant protein RR 0.98 (0.81 to 1.20)
Certainty: Dietary protein from foods, not powders; association, not cause. GRADE moderate for total and animal protein.
Clin Nutr, 2024 · checked 2026-10-06 · we read the abstract
ev-ppreg-08 · Observational data · systematic review and dose-response meta-analysis of prospective observational studies · n = 115496
There was moderate certainty evidence that animal-sourced protein (HvL: RR 1.62 (95% CI 1.20 to 2.18) I2 82%) and animal-sourced fat (HvL: RR 1.59 (95% CI 1.34 to 1.88) I2 0%) intakes were associated with higher GDM in a dose-response manner.
Who: Pregnant women, 25 prospective observational studies
Effect: animal-sourced protein highest vs lowest RR 1.62 (95% CI 1.20 to 2.18), I2 82%, dose-response, moderate certainty
Certainty: Food protein, not supplements; high heterogeneity.
BMC Med, 2026 · checked 2026-10-06 · we read the abstract
ev-ppreg-09 · Position of an expert body · WHO guideline recommendation · n = —
In undernourished populations, high-protein supplementation is not recommended for pregnant women to improve maternal and perinatal outcomes
Who: Pregnant women in undernourished populations
Effect: recommendation against high-protein supplementation (WHO ANC guideline 2016)
Certainty: Two independent requests: WebSearch returned the sentence verbatim from WHO eLENA; WebFetch of the BIGG/PAHO guideline register confirmed the same wording, source WHO ANC 2016.
WHO, 2016, WHO recommendations on antenatal care for a positive pregnancy experience (eLENA summary) · checked 2026-10-06 · we read the section
ev-ppreg-10 · Position of an expert body · regulatory reference value · n = —
In the preamble to the proposed rule (79 FR 11879 at 11943), we noted that the IOM established 71 grams/day protein as the RDA for pregnant and lactating women based on the needs for maternal and fetal development and human milk production.
Who: Pregnant and lactating women, US labeling
Effect: RDA 71 g/day protein in pregnancy (IOM), RDI 71 g on labels for pregnant and lactating women
Certainty: Sets the target intake for labels; says nothing about how women reach it.
FDA, 2016, Food Labeling: Revision of the Nutrition and Supplement Facts Labels, final rule (FR Doc. 2016-11867) · checked 2026-10-06 · we read the section
ev-ppreg-11 · Position of an expert body · agency systematic review, background section · n = —
A higher EAR and RDA is also observed during pregnancy and lactation (EAR: 0.88-1.05 g/kg/d, RDA: 1.1-1.3 g/kg/d).
Who: Pregnant and lactating women, DRI reference values
Effect: EAR 0.88 to 1.05 g/kg/d; RDA 1.1 to 1.3 g/kg/d in pregnancy and lactation
Certainty: Background statement of the reference values, not a new analysis.
AHRQ, 2024, Evaluation of Dietary Protein and Amino Acid Requirements: A Systematic Review · checked 2026-10-06 · we read the section
ev-ppreg-12 · Laboratory or animal data · laboratory analysis of commercial products (ICP-MS) with health-risk modeling · n = 30 products
While all samples contained at least one target metal, plant-derived products exhibited higher mean Pb (0.18 mg/kg) and Cd (0.05 mg/kg) levels compared to dairy-derived products (0.06 and 0.01 mg/kg, respectively; P < 0.01).
Who: 30 commercial sports protein supplements sold in China
Effect: mean Pb 0.18 mg/kg plant vs 0.06 mg/kg dairy; Cd 0.05 vs 0.01 mg/kg
Certainty: Product testing, not a study of pregnant women.
Environmental Research, 2026 · checked 2026-10-06 · we read the abstract
ev-ppreg-13 · Laboratory or animal data · laboratory analysis of commercial products (ICP-OES) with dietary exposure assessment · n = 56 samples
At the recommended consumption level of 30 g/day, exposure to both essential and PTEs did not exceed reference intake limits.
Who: 56 plant-based protein supplement samples from European sources
Effect: at 30 g/day no reference intake limit exceeded
Certainty: Product testing, not pregnancy outcomes; risk depends on dose and brand.
Journal of Trace Elements in Medicine and Biology, 2025 · checked 2026-10-06 · we read the abstract
prsp-daily-r1-09 · Meta-analysis or systematic review · individual participant data meta-analysis of RCTs · n = 12549
Compared to the comparison group, prenatal BEP led to a 6% greater GWG percent adequacy (95% CI: 2.18, 9.56; p = 0.002), a 0.59 kg greater estimated total GWG at delivery (95% CI, 0.12, 1.05; p = 0.014), a 10% lower risk of severely inadequate GWG (RR: 0.90; 95% CI: 0.83, 0.99; p = 0.025), and a 7% lower risk of inadequate GWG (RR: 0.93; 95% CI: 0.89, 0.97; p = 0.001).
Who: 11 RCTs, 12,549 pregnant women in low- and middle-income countries
Effect: GWG adequacy +6% (2.18 to 9.56); total GWG +1.3 lb (0.26 to 2.3; metric: 0.59 kg, 0.12 to 1.05); inadequate GWG RR 0.93 (0.89 to 0.97)
Certainty: balanced energy-protein supplements for the undernourished, not a sports powder
PLoS Med, 2025 · checked 2026-09-29 · we read the abstract

How this page was made. Evidence was extracted from primary sources into cards, every number was re-checked against the source, and the text was written from those cards. Bioma Learn has no human medical reviewer at this time, and we say so rather than invent one. Methodology. This is information, not medical advice.