Are chia seeds safe during pregnancy?

Nobody can say for certain. We found no study that tested whole chia seeds in pregnant women. A 2018 meta-analysis of 12 randomized chia trials found participants who were healthy adults, athletes and people with diabetes or metabolic syndrome, and none who were pregnant. Outside pregnancy, the EU food safety agency reviewed human trials using up to 50 g a day and found no adverse events related to chia. The only trial in pregnancy used chia oil, in 40 Chilean women, and measured fatty acids rather than how the pregnancy went.

Unsettled. Safety in pregnancy is an inference here, not a finding. The EFSA statement rests on trials in non-pregnant adults that checked few safety endpoints. We found no randomized trial and no cohort of chia seeds in pregnant women, and nothing on gestational diabetes, birth weight, preterm birth or chia allergy in pregnancy.

What the trials found

The one trial in pregnant women was run in Chile. Forty healthy women aged 22 to 35 were randomized, 19 to take 1.1 tbsp (16 mL) of chia oil a day from the third trimester through 6 months of nursing and 21 to eat normally. There was no placebo. Blood levels of ALA and EPA rose, and blood DHA did not change. In breast milk, ALA stayed higher for 6 months, and DHA was higher only in the first three months of nursing. It was an oil, not whole seeds, and the trial reported fatty acid markers, with no clinical outcome for mother or baby.

The other evidence is indirect, and it is easy to stretch too far. Chia seeds are a source of fiber and of the plant omega-3 ALA, and both have trials in pregnancy that did not use chia.

For constipation, a Cochrane review found that fiber supplements gave pregnant women with constipation 2.24 more stools a week than no treatment (95% CI 0.96 to 3.52). That rests on one trial of 40 women at moderate risk of bias, rated moderate quality, and none of the fiber was chia.

For omega-3, a meta-analysis of 59 randomized trials found that supplements in pregnancy lowered the risk of birth before 37 weeks by 14% (RR 0.86, 95% CI 0.77 to 0.95, 27 comparisons in 15,510 women). The abstract gives no absolute rates. Those trials mostly gave fish-type DHA and EPA. Chia gives only ALA, and in the Chilean trial chia oil did not raise mothers' blood DHA, so this benefit cannot be credited to chia.

Myth. Chia seeds are sometimes sold to pregnant women as a plant source of the omega-3 that matters for the baby. In the only pregnancy trial, 1.1 tbsp (16 mL) of chia oil a day did not raise blood DHA, the omega-3 given in most of the trials behind the preterm birth result.

Who should be careful

Not for everyone. Dry chia seeds absorb a lot of water and swell into a gel. A 2017 case report describes that gel blocking the esophagus of one adult with likely eosinophilic esophagitis, which needed an endoscopy to clear. It is a single case, not in pregnancy. It is the reason to soak chia or take it with plenty of fluid, and to be cautious if you have trouble swallowing.

Allergy is the second caution. The EU food safety agency says allergic reactions to chia seeds may occur, on the strength of two case reports from Spain, and nobody knows how common chia allergy is or whether pregnancy changes it. Very large amounts are a third. A 59-year-old woman eating six tablespoons of chia and five handfuls of almonds a day developed calcium oxalate deposits in her kidneys, with creatinine rising from 1.3 to 1.8 mg/dL, and her results improved on a low-oxalate diet. The almonds contributed, it is one case and she was not pregnant. We found no entry for chia in the US drug and lactation database and no recorded drug interaction.

What expert bodies say

The European Food Safety Authority assessed chia seeds as a novel food in 2019. Reviewing human studies at up to 50 g a day, it found no changes in the safety measures studied and no adverse events related to chia. None of those studies was in pregnant women, and they checked few safety endpoints. We found no expert body with advice on chia seeds in pregnancy specifically.

How we searched

What would change this answer

• A cohort study that records chia seed intake in pregnancy and follows gestational diabetes, birth weight and preterm birth. We found none.
• A randomized trial of whole chia seeds in pregnant women, at an ordinary food amount, reporting tolerance, constipation and blood sugar. ClinicalTrials.gov lists none.
• The ALA-only results inside the omega-3 meta-analysis, which would show whether plant omega-3 does anything for preterm birth.
• Any data on how common chia allergy is, in pregnancy or outside it.

More on chia, including what the trials on cholesterol, blood sugar and weight found: chia seeds →

Sources

1. ev-chiap-01 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 12 trials
   Participants included healthy persons, athletes, diabetic patients, and individuals with metabolic syndrome.
   
   Who: healthy persons, athletes, diabetic patients and individuals with metabolic syndrome in randomized trials of chia seed
   Effect: no pregnant participants; pooled results not significant except subgroup findings at higher doses; GRADE low or very low; surrogate outcomes only
   Certainty: The absence of pregnancy data is the finding; the 2026-10-07 web and ClinicalTrials.gov searches found no chia trial in pregnancy.
   Nutr Rev, 2018 · checked 2026-10-07 · we read the abstract
2. ev-chiap-02 · Randomized controlled trial(s) · randomized controlled trial, 16 mL/day chia oil from the third trimester to 6 months of nursing, no placebo · n = 40
   Consumption of chia oil during the last trimester of pregnancy and the first three months of nursing transiently increases the milk content of DHA.
   
   Who: forty healthy pregnant women aged 22-35 years, chia group n=19, control group with normal feeding n=21
   Effect: blood ALA and EPA rose, blood DHA unchanged; milk ALA higher for 6 months, milk DHA higher only in months 1-3
   Certainty: Chia oil, not whole seeds; small open trial; fatty-acid markers only, no clinical pregnancy or infant outcomes.
   Nutrients, 2015 · checked 2026-10-07 · we read the abstract
3. ev-chiap-03 · Meta-analysis or systematic review · Cochrane systematic review of randomized and quasi-randomized trials · n = 40
   Pregnant women who received fibre supplementation had significantly higher frequency of stools compared to no intervention (mean difference (MD) 2.24 times per week, 95% CI 0.96 to 3.52; 40 women, one study, moderate quality of evidence).
   
   Who: pregnant women with constipation, fiber supplementation versus no intervention
   Effect: stool frequency MD 2.24 per week (95% CI 0.96 to 3.52), moderate quality evidence, one study
   Certainty: Fiber supplements, not chia; one small trial with moderate risk of bias. Chia is relevant here only as a fiber source.
   Cochrane Database Syst Rev, 2015 · checked 2026-10-07 · we read the abstract
4. ev-chiap-04 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized and quasi-randomized trials · n = 15510
   27 comparisons (15,510 women) was accompanied by a significant decrease in pre-term birth less than 37 weeks (RR = 0.86, 95% CI 0.77-0.95, p = 0.005; I2 = 0%).
   
   Who: pregnant women given DHA, EPA and/or ALA supplements versus no supplement or placebo
   Effect: preterm birth <37 weeks RR 0.86 (95% CI 0.77 to 0.95), 27 comparisons, I2 0%
   Certainty: Chia supplies ALA only; in ev-chiap-02 chia oil did not raise maternal blood DHA, so this benefit cannot be transferred to chia. ALA-only subgroup not readable (abstract only).
   Arch Gynecol Obstet, 2023 · checked 2026-10-07 · we read the abstract
5. ev-chiap-05 · Position of an expert body · scientific opinion of the EFSA NDA Panel (novel food safety assessment) · n = 2 case reports
   The information available indicates that allergic reactions upon consumption of chia seeds may occur.
   
   Who: consumers of chia seeds; case reports from Spain
   Effect: allergic reactions reported in case reports; prevalence of chia allergy unknown
   Certainty: Case reports only; nothing specific to pregnancy.
   EFSA Journal, 2019, Safety of chia seeds (Salvia hispanica L.) as a novel food for extended uses pursuant to Regulation (EU) 2015/2283 · checked 2026-10-07 · we read the fulltext
6. ev-chiap-06 · Position of an expert body · scientific opinion of the EFSA NDA Panel (novel food safety assessment) · n = —
   The Panel notes that no changes were found in the studied safety-related parameters and no adverse events related to the consumption of chia seeds were reported.
   
   Who: adults in human studies of chia seeds reviewed by EFSA, up to 50 g/day
   Effect: no changes in safety-related parameters and no chia-related adverse events reported
   Certainty: Pregnancy is not covered by the trials EFSA reviewed (ev-chiap-01 lists the populations); the safety statement rests on general population use.
   EFSA Journal, 2019, Safety of chia seeds (Salvia hispanica L.) as a novel food for extended uses pursuant to Regulation (EU) 2015/2283 · checked 2026-10-07 · we read the fulltext
7. ev-chiap-07 · Laboratory or animal data · case report · n = 1
   Chia seeds, a staple known for health benefits, have an uncanny ability to absorb large quantities of water leading to a hydrated gel-like substance which can cause an obstruction.
   
   Who: one adult patient with likely eosinophilic esophagitis
   Effect: esophageal food impaction by hydrated chia gel requiring endoscopic clearance
   Certainty: Single case, not pregnant; supports soaking chia or taking it with fluid.
   Case Reports in Internal Medicine, 2017, 4(2):49, Watch it grow: Esophageal impaction with chia seeds · checked 2026-10-07 · we read the abstract
8. ev-chco-07 · Laboratory or animal data · case report · n = 1
   Diet included six tablespoons of chia seeds and five handfuls of almonds daily to manage IBS symptoms.
   
   Who: 59-year-old woman with controlled hypertension managing IBS symptoms by diet
   Effect: creatinine rose from 1.3 to 1.8 mg/dL; biopsy showed calcium oxalate deposition; labs improved after a low-oxalate diet
   Certainty: Single case; almonds contributed; dose far above usual 1 to 2 tablespoons.
   BMJ Case Rep, 2020 · checked 2026-10-06 · we read the abstract