Maternal Peripartum Hyponatraemia Leading to Early Neonatal Seizures: A Case Series

Peripartum hyponatraemia is an underrecognised yet significant electrolyte disturbance that can adversely affect both the mother and the neonate. Labouring women are predisposed to hyponatraemia which can be attributed to lower baseline sodium levels, impaired renal water excretion, and/or the antidiuretic effects of oxytocin. As maternal and foetal electrolytes equilibrate across the placenta, affecting the milieu, maternal hyponatraemia may result in neonatal dyselectrolytaemia and rarely early-onset seizures. In this case series, the authors aim to highlight the importance of sodium homeostasis during pregnancy and labour, to ensure accurate fluid balance monitoring, increase awareness, and hence earlier detection of peripartum hyponatraemia to prevent unfavourable maternal and neonatal outcomes. Three parturients and their neonates who developed significant hyponatraemia were analysed for their course of labour, biochemical parameters, and clinical outcomes. Two patients (Case 1,3) were Robson class I, Case 2 Robson II A. Case 1 had a vacuum-assisted vaginal delivery, the second and third had spontaneous vaginal delivery. Case 2 received Entonox as labour analgesia. Cord blood gases were normal. The three parturients had varied clinical presentation with case 1 being asymptomatic, case 2 slightly drowsy but she was also on Entonox analgesia and case 3 had generalised tonic clonic seizures. All three neonates presented with convulsions on postnatal day 1 and responded to intravenous saline. Sepsis work-up, glucose, and calcium levels were normal. No neurodevelopmental delay was observed in neonates. A high degree of suspicion in oxytocin augmented labour and even in low-risk labouring women is required to prevent the occurrence of dyselectrolytaemia. Timely recognition and treatment can avert serious maternal and neonatal complications.