Effects of intra-amniotic injection of hypertonic saline on uterine activity, blood and amniotic fluid volumes, and electrolyte concentrations

Abstract

Intraovular injection of hypertonic saline successfully initiated labor in 16 patients. There was a net increase in amniotic fluid volume associated with a decreased blood volume within 2 to 4 hours following injection. The sodium chloride in the amniotic sac is diluted by the influx of water and is lost into the maternal circulation where increased serum sodium and chloride concentrations were observed. Amniotic fluid pressures were continuously monitored. Uterine activity increases shortly after injection and continues to increase until delivery is accomplished.