Does the use of a birthing pool in labour contribute to maternal hyponatraemia? Two case reports

Abstract

Maternal hyponatraemia in labour is a recognised consequence of inappropriate fluid management, both as a result of administration of hypotonic intravenous fluid and increased maternal oral fluid intake. Other less common causes of hyponatraemia in labour include inappropriate secretion of antidiuretic hormone (ADH), exogenous administration of oxytocin, reset osmostat and sodium depletion. Patients with hyponatraemia are often asymptomatic, or display non-specific symptoms such as headache, lethargy and confusion. If hyponatraemia remains undetected, symptoms can progress to seizures, coma and death. Maternal hyponatraemia in labour may also cause a corresponding hyponatraemia in the foetus/neonate. We present two recent cases of severe symptomatic maternal hyponatraemia in labour where a birthing pool was utilised, and hypothesise how birthing pool use may increase the likelihood of developing hyponatraemia.

Keywords

• Birthing pool
• hyponatraemia
• labour