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

Abstract

Objective: To investigate the prevalence and aetiology of hypokalaemia in pregnancy.

Methods: 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.

Results: 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.

Conclusions: There was inadequate investigation and follow-up of hypokalaemia, particularly in women in whom an obvious cause was not apparent.

Keywords: Pregnancy; aldosterone; hyperemesis; hypokalaemia; pre-eclampsia; renin.

Figure 1.

Flowchart for the investigation of hypokalaemia in pregnancy.