Is coconut water good during pregnancy and breastfeeding?

Nobody has tested it. We found no randomized trial, no systematic review and no cohort study of coconut water in pregnant or breastfeeding women. The nearest evidence is about drinking more of anything. In pregnancies with low amniotic fluid, a 2025 meta-analysis of mixed designs found extra fluid raised the amniotic fluid index by about 0.39 in (1 cm) within 2 hours, and that analysis did not test coconut water on its own. Against that sits one case report from 2024, a newborn with serum sodium of 113 mmol/L and two seizures after the mother drank excessive amounts of coconut water during labor.

Unsettled. Coconut water is a drink, and in pregnancy it counts toward fluid like any other. Whether it does anything special for nausea, labor or milk supply has not been checked in a study we could find in PubMed, Europe PMC or ClinicalTrials.gov. The claims online rest on a letter and on small local studies outside the journals we can verify.

What the trials found

Extra fluid and amniotic fluid

The 2025 review in the Journal of Perinatal Medicine gathered 12 studies of oral hydration in women with oligohydramnios, the medical name for low amniotic fluid, and could pool 4 of them. The amniotic fluid index rose by 0.996 (95% CI 0.781 to 1.210) at 2 hours and by 2.232 (95% CI 0.943 to 3.520) at 1 week. The designs were mixed and the results varied with the fluid, the volume and how often women drank, so the honest reading is that drinking more helped and coconut water was not tested on its own. Low amniotic fluid is a diagnosis for the obstetric team, and none of this replaces their plan.

What is in the drink

In USDA records, 3.5 oz (100 g) of coconut water carries 250 mg of potassium and 105 mg of sodium, and across the two records sodium runs from 26 to 105 mg. That is from two SR Legacy records only. In 45 coconuts from one region of Brazil, the water held a median of 64 mEq/L of potassium, and the potassium fell as the nut matured. So the drink is rich in potassium, its sodium varies a lot between records, and the exact figures change with the coconut.

The one trial on potassium

In a randomized trial in 32 women aged 25 to 44 with prehypertension, 10 fl oz (300 ml) of tender coconut water twice a day for 14 days did not change plasma potassium compared with the same amount of water. The women were not pregnant, the trial was short and small, and its abstract does not report blood pressure.

Who should be careful

Not for everyone. Very large amounts in labor. A 2024 case report in A&A Practice describes a term baby born with serum sodium of 113 mmol/L who had two seizures, and the authors attributed it to the mother drinking excessive amounts of coconut water during labor. The baby was treated with 3% saline and had no lasting harm. It is one case, and the abstract does not say how much she drank or explain how it happened. Until more is known, very large amounts over many hours of labor are the one pattern linked to harm.

Kidney disease and some heart and blood pressure medicines. The NIH Office of Dietary Supplements says that in people with chronic kidney disease, or taking ACE inhibitors or potassium-sparing diuretics, even dietary potassium below the adequate intake can cause hyperkalemia. It also says very high amounts of potassium can cause acute hyperkalemia even in healthy people, and that sentence is about supplements and salt substitutes, not coconut water. A case report describes a 78-year-old man with renal failure, on losartan and spironolactone, whose serum potassium reached 7.02 mEq/L after a week of heavy king coconut water intake. He had several triggers at once. A 1992 trial in children with diarrhea that found young coconut water usable as home rehydration in mild illness warned against it where kidney function is impaired. If you are pregnant and have kidney disease or take one of these drugs, ask the person treating you before drinking it daily.

Old or spoiled coconuts. A 2021 report in Emerging Infectious Diseases describes a man in Denmark, not pregnant and aged 69, who died after drinking a little water from a ready-to-drink coconut kept unrefrigerated for a month. The water was spoiled by a fungus that makes 3-nitropropionic acid. Keep fresh coconuts cold and do not drink water that tastes off or looks slimy.

We found no evidence either way on breastfeeding. LactMed, the US database of what passes into breast milk, has no record for coconut, and that is an absence of data, not a sign of safety.

What expert bodies say

We found no guideline from an obstetric or nutrition body on coconut water in pregnancy or breastfeeding. The only position that applies is the NIH Office of Dietary Supplements on potassium above, which is not specific to pregnancy. More on the drink itself is on the coconut water page.

How we searched

What would change this answer

• A randomized trial of coconut water for nausea and vomiting of pregnancy or hyperemesis, published in a journal indexed in PubMed. None was registered on ClinicalTrials.gov on 6 October 2026.
• A trial comparing coconut water with oral rehydration solution during labor, measuring sodium in mother and baby.
• Any study of coconut water during breastfeeding.
• The full text of the 2025 meta-analysis, to see whether coconut water was one of the fluids pooled.

Sources

1. ev-cwpg-01 · Laboratory or animal data · case report · n = 1
   The severe neonatal hyponatremia and seizures were attributed to maternal consumption of excessive amounts of coconut water during labor.
   
   Who: One term neonate and the mother, who drank coconut water during labor
   Effect: neonatal serum sodium 113 mmol/L, two seizures, corrected with 3% saline without sequelae
   Certainty: A single case; the volume of water drunk is not named in the abstract. Mechanism: coconut water is very low in sodium (~3 mEq/L, cwat-r2-02), so large volumes in labor act as a hypotonic fluid.
   A&A Practice, 2024 · checked 2026-10-06 · we read the abstract
2. ev-cwpg-02 · Observational data · systematic review and meta-analysis of randomized, quasi-experimental and observational studies · n = 12 studies
   Pooled results showed a significant increase in AFI at 2 hours (mean difference: 0.996; 95 % CI: 0.781-1.210), 1 day (0.853; 95 % CI: 0.532-1.174), 2 days (1.649; 95 % CI: 0.943-2.356), and 1 week (2.232; 95 % CI: 0.943-3.520).
   
   Who: Pregnant women with oligohydramnios in 12 studies (RCTs, quasi-experimental and observational), 4 pooled
   Effect: AFI mean difference 0.996 (95% CI 0.781 to 1.210) at 2 hours; 2.232 (95% CI 0.943 to 3.520) at 1 week; high heterogeneity by fluid type, volume and frequency
   Certainty: About hydration with any fluid, not coconut water separately; only 4 studies in the meta-analysis, mixed designs. For the page: the effect comes from fluid volume, not from anything specific to coconut water.
   Journal of Perinatal Medicine, 2025 · checked 2026-10-06 · we read the abstract
3. ev-cwpg-03 · Position of an expert body · fact sheet · n = —
   However, in people with impaired urinary potassium excretion due to chronic kidney disease or the use of certain medications, such as angiotensin converting enzyme (ACE) inhibitors or potassium-sparing diuretics, even dietary potassium intakes below the AI can cause hyperkalemia [11].
   
   Who: People with impaired urinary potassium excretion, NIH potassium fact sheet
   Effect: hyperkalemia possible even at dietary potassium intakes below the AI
   Certainty: Not about pregnancy separately; applies to pregnant women with kidney disease or on potassium-sparing drugs. ODS also: with healthy kidneys, dietary potassium carries no risk, no UL set.
   NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section
4. ev-cwpg-04 · Laboratory or animal data · case report · n = 1
   The cause of death was poisoning with 3-nitropropionic acid from coconut water spoiled with the fungus Arthrinium saccharicola.
   
   Who: One 69-year-old man, Denmark
   Effect: fatal encephalopathy from 3-nitropropionic acid in spoiled coconut water
   Certainty: Not about pregnancy; concerns food safety of fresh coconut: keep in the refrigerator, do not drink water with an unpleasant taste or slimy contents.
   Emerging Infectious Diseases, 2021 · checked 2026-10-06 · we read the fulltext
5. cwat-r2-01 · Position of an expert body · USDA reference dataset · n = 2 records
   Nuts, coconut water (liquid from coconuts) (FDC 170174, SR Legacy, Nut and Seed Products): magnesium 25 mg per 100 g = 6% DV; potassium 250 mg = 5% DV; sodium 105 mg = 5% DV; across 2 records magnesium 6-25, potassium 165-250, sodium 26-105; Foundation samples 0, CoFID match none
   
   Who: USDA SR Legacy records for Nuts, coconut water (liquid from coconuts) and Beverages, Coconut water, ready-to-drink
   Effect: potassium 250 mg per 3.5 oz (100 g) (5% DV), sodium 105 mg (5% DV), magnesium 25 mg (6% DV); range across 2 records potassium 165 to 250, sodium 26 to 105, magnesium 6 to 25 mg
   Certainty: Two SR Legacy entries, no Foundation, no spread across samples; CoFID gives no second number.
   USDA FoodData Central, SR Legacy, FDC 170174 · checked 2026-09-29 · we read the dataset
6. cwat-r2-02 · Observational data · cross-sectional laboratory analysis · n = 45
   Coconut water from a total of 45 coconuts, from the sixth to ninth months' maturity, were analyzed to measure glucose, electrolytes, total proteins and osmolarity and to identify the sugars contained...detected a reduction in the concentration of potassium (64 mEq/L; 46 and 99), calcium (6.5 mmol/L; 5 and 8.5), magnesium (8 mmol/L; 3.9 and 9.8), chloride (38.5 mEq/L; 30 and 48.7) and osmolarity (419 mOsmol/L; 354 and 472).
   
   Who: Coconut water from 45 coconuts of dwarf palms in a non-coastal region of Brazil, 6 to 9 months maturity
   Effect: median potassium 64 mEq/L (46 to 99), sodium 3 mEq/L, osmolarity 419 mOsmol/L (354 to 472), falling with maturity
   Certainty: A single region and variety; shows that composition depends on nut ripeness.
   J Pediatr (Rio J), 2006 · checked 2026-09-29 · we read the abstract
7. cwat-r2-06 · Randomized controlled trial(s) · parallel randomized clinical trial · n = 32
   Thirthy-two female aged 25-44 years were randomly allocated to 14 days on TCW or water in a parallel randomized clinical trial. The treatment (T) group received TCW 300 ml twice daily and the control (C) group received water 300 ml twice daily too...After 14 days treatment, potassium plasma level between T and C groups were not significantly different (p=0,247).
   
   Who: Women aged 25 to 44 with prehypertension, 14 days
   Effect: no significant difference in plasma potassium between groups (p = 0.247)
   Certainty: Short and few participants; blood pressure as an outcome is not given in the abstract.
   Curr Hypertens Rev, 2017 · checked 2026-09-29 · we read the abstract
8. cwat-r2-09 · Position of an expert body · fact sheet · n = —
   However, very high amounts of potassium supplements or salt substitutes that contain potassium could exceed the kidney’s capacity to excrete potassium, causing acute hyperkalemia even in healthy individuals.
   
   Who: General population, NIH potassium fact sheet
   Effect: acute hyperkalemia possible with very high potassium amounts
   Certainty: About supplements and salt substitutes, not coconut water; the threshold for food is not named.
   NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals · checked 2026-09-29 · we read the section
9. cwat-r2-10 · Laboratory or animal data · case report · n = 1
   We report the case of acute ascending flaccid paralysis secondary to hyperkalemia induced by multiple trigger factors-king coconut water, renal failure, diabetes, metabolic acidosis, and potassium sparing diuretics. CASE PRESENTATION: A 78-year-old man presented with acute ascending type flaccid paralysis over five-hour duration and subsequently developed preterminal cardiac arrhythmias secondary to severe hyperkalemia (serum potassium: 7.02 mEq/L). He was on Losartan and Spironolactone for ischemic heart disease. Dietary history revealed excessive intake of king coconut water (Cocos nucifera) over past one week.
   
   Who: One 78-year-old man with renal failure, diabetes and ischemic heart disease
   Effect: serum potassium 7.02 mEq/L, preterminal arrhythmia, full neurological recovery within 24 h
   Certainty: A single case, several triggers at once (renal failure, medications, acidosis).
   Case Rep Neurol Med, 2018 · checked 2026-09-29 · we read the abstract
10. cwat-r2-12 · Randomized controlled trial(s) · randomized clinical trial · n = —
    Our results suggest that young coconut water can be used, together with early refeeding, as a home glucose electrolyte oral rehydration solution in the early stages of mild diarrhoeal disease, despite not having a balanced electrolyte composition. However, it should not be used in patients with severe cholera, or in patients who are dehydrated and/or in whom renal function is impaired.
    
    Who: Well-nourished children with mild diarrhea, Trinidad and Tobago
    Effect: usable as home glucose electrolyte solution in early mild diarrhea; electrolyte composition not balanced
    Certainty: 1992, abstract without numbers and without sample size; no full text.
    Trop Geogr Med, 1992 · checked 2026-09-29 · we read the abstract