Aim: To identify the prevalence, maternal characteristics and potential associations/aetiologies of acute severe hyperkalaemia (serum potassium > 5.9mmol/L) in pregnancy at a tertiary referral obstetric hospital in Brisbane, Australia.
Methodology:
Retrospective audit of a pathology database from January 2006 to December 2025.
Results:
52 cases of hyperkalaemia were identified from 108424 pregnancies. Hyperkalaemia complicated 1 in 2085 pregnancies (0.0048%).
Mean maternal age was 32 years, mean BMI was 24.5 kg/m2, and mean gestation at hyperkalaemia was 33 weeks. 39 women (75%) were nulliparous. Mean peak serum potassium was 6.5 mmol/L (6.0-7.6mmol/L).
Hyperkalaemia was predominantly multifactorial in 2 groups. 31 women with preeclampsia included associations/potential aetiologies of magnesium infusion (26), acute kidney injury [(AKI): n=26 - mean/median serum creatinine 132/102 umol/L], labetalol therapy (17), HELLP syndrome (6), postpartum haemorrhage (4) and DIC (3). 21 women with obstetric haemorrhage requiring blood transfusion had potential associations of DIC (15), AKI (5) and preeclampsia (4). 3 women developed hyperkalaemia with AKI alone, and one following intrauterine fetal demise. Suxamethonium administration (2 women) was not temporally causative. There were no adverse maternal sequelae of hyperkalaemia.
Conclusion:
Acute severe hyperkalaemia is uncommon in pregnancy. Clinicians should be aware of the risk of acute hyperkalaemia in preeclampsia complicated by HELLP syndrome, AKI, magnesium infusion and/or DIC, and following blood transfusion for obstetric haemorrhage particularly in the setting of AKI and/or DIC. The role of labetalol therapy in acute hyperkalaemia is unclear.