Hypokalaemia in pregnancy – Prevalence, underlying causes, and an approach to investigation

To investigate the prevalence and aetiology of hypokalaemia in pregnancy. This was a five-year retrospective audit of women who received care at a tertiary hospital, who developed hypokalaemia during pregnancy and within three weeks postpartum. Serum potassium and magnesium levels cause(s) of hospitalization and investigations for hypokalaemia were obtained from hospital records. One hundred and ten women developed hypokalaemia during pregnancy and the immediate postpartum period, representing 0.36% of total births. Ninety-one per cent of patients had mild to moderate hypokalaemia (K 2.6–3.1 mmol/L), while 9% had severe hypokalaemia (K < 2.6 mmol/L). The most common associations of hypokalaemia were infection (38%), vomiting (18%), hypertensive disorders (12%) and postpartum haemorrhage (9%). Twenty-four patients did not have a clear underlying aetiology of hypokalaemia, but only five had further investigations. There was inadequate investigation and follow-up of hypokalaemia, particularly in women in whom an obvious cause was not apparent.