Potassium

In this article, we’ll explore the ideal potassium ranges, the causes behind high or low levels, and how the unique physiology of pregnancy influences these reference values. By examining potassium’s role more closely, we can better support maternal health and optimize pregnancy outcomes.

Potassium Testing

The potassium test measures the concentration of potassium in the blood. 

The sodium-potassium adenosine triphosphatase pump regulates the homeostasis between sodium and potassium, which moves sodium out of cells in exchange for potassium, which moves into the cells. This process requires magnesium. The filtration of potassium takes place at the glomerulus of the kidneys. Aldosterone increases potassium excretion from the kidneys.

Potassium in Pregnancy

​During the first trimester, serum potassium levels may decrease slightly. This decrease is likely due to increased renal blood flow and glomerular filtration rate (GFR), which can lead to increased kidney potassium excretion. This decrease slows in the second trimester and plateaus by 28 weeks, after which levels increase, reaching their peak near the end of pregnancy. 

​Significant increases in plasma potassium and sodium concentrations occur in the first six weeks postpartum when plasma chloride concentration falls. 

High Potassium in Pregnancy

Elevated potassium occurs in <1% of pregnancies.
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High potassium levels, >5 mmol/L, during the first half of pregnancy, are associated with, are associated with a higher risk for the development of gestational diabetes mellitus (GDM) and severe preeclampsia. 

Most Common Causes of High Potassium in Pregnancy

• Dehydration
• Hemolysis
• Adrenal Hypofunction
• Hypothyroidism
• Renal Dysfunction
• Certain Medications (potassium-sparing diuretics), angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), nonsteroidal anti-inflammatory drugs (nonsteroidal anti-inflammatories)
• Recent Blood Transfusion
• Anemia

Low Potassium in Pregnancy

​Hypokalemia occurs when serum potassium levels are under 3.6 mmol/L. 

Most Common Causes of Low Potassium in Pregnancy

• Severe Hyperemesis Gravidarum/Periods of Malnutrition
• Low Progesterone
• Magnesium Deficiency
• Hyperthyroidism
• Certain Medications (asthma medications, laxatives)
• Genetics

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Medical Disclaimer:
This content is for educational purposes only and is intended for licensed medical professionals. It is based on current research, subject to change, and not intended to diagnose, treat, or prevent any medical condition. This information does not replace consultation with a qualified healthcare provider. Seek professional medical evaluation and treatment from a licensed provider. Use of this information is at your own risk.​

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