Hello and I hope I can help you today. It is a bit unusual to find a high potassium level in someone with no other health problems. So I would first have the test repeated as soon as possible to make sure it is not a lab error. At a level of 5.9 (normal is up to 5.2) is really not dangerous, but it should be monitored. It can be lowered if necessary with medication. Your doctor should also evaluate your kidney function and also check for diabetes as these can cause high potassium levels. So I encourage you to get the blood tests recommended by your provider- but your level is not dangerous at this time. I hope this information was helpful and that I adequately answered your question. Best of luck with the rest of your pregnancy, Dr. Brown