Iatrogenic neonatal and maternal hyponatraemia following oxytocin and aqueous glucose infusion during labour

Publisher Website
Google Scholar
Abstract
Maternal and umbilical cord serum Na and osmolality were studied prospectively in 140 deliveries to investigate whether transplacental hyponatremia, seen following oxytocin infusion during labor, was due to the antidiuretic effect of oxytocin or was secondary to the infusion of aqueous glucose used as a vehicle for oxytocin, or both. Forty-five women received oxytocin in aqueous glucose for induction or augmentation of labor (oxytocin group), 43 received aqueous glucose infusion alone (glucose group) and 52 did not receive any intravenous infusions (control group). Mean cord sodium levels were significantly lower in the oxytocin (131.4, SD 3.6 mmol/l) and glucose groups (132.5, SD 3.2 mmol/l) than in the control group (135.0, SD 3.0 mmol/l). Hyponatremia (Na < 130 mmol) was seen in 47 and 30% of the infants in the oxytocin and glucose groups, respectively, in contrast to only 5.8% of the infants in the control group. Significant negative linear correlations were seen between serum Na and the dose of oxytocin (P < 0.01) and log of the volume of glucose solution infused (P < 0.001). The hyponatremic newborn infants had a significantly higher incidence of transient neonatal tachypnea (7/37, 19%) than the normonatremic infants (2%). Results strongly suggest that infusion of oxytocin and glucose both cause maternal and transplacental hyponatremia, even in recommended doses. This should be taken in account while planning a safe dose of oxytocin and glucose for infusion during labor.