Quick answer

NIH lists 2,900 mg of potassium a day for pregnancy and sets no upper limit for healthy people. The potassium chloride label says supplementation that does not lead to hyperkalemia is not expected to cause fetal harm, while the potassium citrate label says it is not known. Ask your doctor first with kidney disease or blood pressure medicine.^1,2,3,4

Key facts

NIH lists 2,900 mg of potassium a day for pregnant women and 2,600 mg for pregnant teens.¹
NIH sets no upper limit for potassium in healthy people with normal kidney function, because the kidneys pass the excess.²
The potassium chloride label says there are no human data in pregnancy and that supplementation not leading to hyperkalemia is not expected to cause fetal harm.³
The potassium citrate label says it is not known whether the drug can cause fetal harm and that it should be given in pregnancy only if clearly needed.⁴
Most potassium supplements hold 99 mg or less per serving, about 2% of the Daily Value.^1,2

How much potassium does NIH list for pregnancy?

Women need about 2,600 mg of potassium a day from all sources, 2,900 mg during pregnancy and 2,800 mg while breastfeeding.^1,2

NIH says the adequate intake for pregnant teens is 2,600 mg a day. It adds that most Americans eat less potassium than recommended, which is why US dietary guidelines call it a nutrient of public health concern.^1,2

Among Americans who take a supplement containing potassium, it adds only about 87 mg a day on average, and supplement use does not significantly raise total intake.²

What do drug labels say about potassium in pregnancy?

The prescription potassium chloride label says there are no human data on use in pregnancy and that animal reproduction studies have not been conducted. It says potassium supplementation that does not lead to hyperkalemia, meaning too much potassium in the blood, is not expected to cause fetal harm.³

The potassium citrate label says animal studies have not been conducted, that it is not known whether the drug can cause fetal harm or affect reproduction, and that it should be given to a pregnant woman only if clearly needed.⁴

Both labels cover prescription drugs, which can supply more potassium than the supplements most people buy, most of which hold 99 mg or less per serving. They show what is and is not known for the drugs, not a finding about a supplement.^2,3

When does extra potassium become a problem?

Very large amounts of potassium from supplements or salt substitutes can exceed what the kidneys can clear and cause hyperkalemia even in healthy people. In people with kidney disease or on certain medicines, it can happen even at ordinary food intakes.^1,2

NIH says people with kidney disease or who take ACE inhibitors, potassium-sparing diuretics and some other medicines can develop hyperkalemia even at normal food intakes. It can also occur with type 1 diabetes, heart failure, liver disease or adrenal insufficiency.²

Many salt substitutes replace some or all of the sodium chloride in salt with potassium chloride, at about 440 to 2,800 mg of potassium per teaspoon.²

What about potassium sorbate, acesulfame potassium and potassium iodide?

These share a word with the mineral but are different substances. Acesulfame potassium is a sweetener and potassium sorbate a food preservative. The sources checked do not address either in pregnancy, which is not a finding either way, so ask your doctor or pharmacist.

Supplement Facts panels list the amount of potassium itself, not the weight of the whole compound. Potassium iodide on a label is there as a source of iodine, in microgram amounts, not as a source of potassium.²

Who should ask a doctor about potassium in pregnancy?

Anyone with kidney disease or reduced kidney function.²
Anyone taking an ACE inhibitor, an ARB, a diuretic or a regular pain reliever such as ibuprofen.^2,3
Anyone with type 1 diabetes, heart failure, liver disease or adrenal insufficiency.²
Anyone who uses a salt substitute, since many replace some or all of the sodium chloride with potassium chloride.²

Ask your doctor before adding potassium beyond a prenatal vitamin or food, and bring the labels of everything you take.

Questions people ask

Is potassium chloride safe during pregnancy?

The prescription label says there are no human data and that supplementation not leading to hyperkalemia is not expected to cause fetal harm. Many salt substitutes use potassium chloride, so ask your doctor before using one.^2,3

Is potassium citrate safe during pregnancy?

The prescription label says it is not known whether potassium citrate can cause fetal harm and that it should be given in pregnancy only if clearly needed. Ask your doctor or pharmacist.⁴

Is acesulfame potassium safe during pregnancy?

The sources checked do not address acesulfame potassium in pregnancy. That is not a finding either way, so ask your doctor or pharmacist.

Is potassium sorbate safe during pregnancy?

The sources checked do not address potassium sorbate in pregnancy. That is not a finding either way, so ask your doctor or pharmacist.

Is potassium OK during pregnancy?

NIH lists 2,900 mg a day from all sources and sets no upper limit for healthy people with normal kidney function. Ask your doctor if you have kidney disease or take blood pressure medicine.^1,2

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Sources

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