The increased body water in pregnant women and the birth-related activation of water-sparing systems contribute to a high risk of perinatal water intoxication if the mother drinks too much water during labour. This study reports on four newborn term infants and one mother presenting with life-threatening symptoms due to hyponatraemia from excessive oral intake during labour. Awareness of this diagnosis in the delivery unit is very important, because the clinical picture may mimic that of pre-eclampsia or dehydration.
Conclusion: Guidelines are proposed to prevent and treat perinatal water intoxication due to excessive oral intake during labour.