Changes in amniotic fluid prostaglandins with oxytocin-induced labor.

Amniotic fluid prostaglandin levels were measured serially in 15 patients who underwent successful induction of labor and compared with those of patients presenting in spontaneous labor. At comparable cervical dilation the induced group demonstrated significantly lower prostaglandin levels. Four of these patients delivered without any increment in prostaglandins while in the remaining patients increases in prostaglandins followed the attainment of efficient uterine contractions by several hours. These data support the hypothesis that oxytocin acts directly on myometrial cells and not primarily by prior generation of prostaglandin synthesis in the membranes.