Such therapy improved the heart rate pattern in half of the women studied. Later, .Miyazaki and Nevarez (1985) randomly assigned 96 nulliparas in labor with cord compression patterns and found that those who were treated with amnioinfusion required cesarean delivery for fetal distress less often. Based on many of these early reports, transvaginal amnioinfusion has been extended into three clinical areas (Dad, 2016). hese include: (1) treatment of variable or prolonged decelerations; (2) prophylaxis for women with oligohydramnios, as with prolonged ruptured membranes; and (3) attempts to dilute or wash out thick meconium (Chap. 33, p. 620).
Many diferent amnioinusion protocols have been reported, but most provide a 500-to 800-mL bolus of warmed normal saline followed by a continuous inusion of approximately 3 mLimin (Owen, 1990; Pressman, 1996). In another study, Rinehart and colleagues (2000) gave either a 500-mL bolus of normal saline at room temperature alone or a similar bolus plus a continuous inusion at 3 mLimin. heir study included 65 women with variable decelerations, and the investigators found neither method to be superior. Wenstrom and associates (1995) surveyed use of mnioinusion in teaching hospitals in the United States. The procedure was used in 96 percent of the 186 centers surveyed, and it was estimated that 3 to 4 percent of llwomen delivered at these centers received such inusion. Potential complications of mnioinusion are summarized in Table 24-4.
TABLE 24-4. Complications Associated with Amnioinfusion from a Survey of 186 Obstetrical Units
Data from Wenstrom, 1995.
able or prolonged decelerations attributed to cord entrapment.
For variable decelerations, Hofmeyr and Lawrie (2012) reviewed the efects of amnioinfusion in the management of fetal heart rate patterns associated with umbilical cord compression. They concluded that amnioinfusion appeared to be useful in reducing the occurrence of variable decelerations, improving neonatal outcome, and lowering cesarean delivery rates. The American College of Obstetricians and Gynecologists (2016) has concluded that amnioinfusion is a reasonable approach in the treatment of repetitive variable decelerations regardless of meconium status.
For oligohydramnios, amnioinfusion has been used prophylactically to avoid intrapartum fetal heart rate patterns from cord occlusion. Nageotte and coworkers (1991) found that this resulted in signiicantly fewer and less severe variable decelerations in labor. However, the cesarean delivery rate or condition of term newborn was not improved. In a randomized investigation, Macri and colleagues (1992) studied prophylactic amnioinfusion in 170 term and postterm pregnancies complicated by both thick meconium and oligohydramnios. Amnioinfusion significantly reduced meconium aspiration syndrome rates and cesarean delivery rates for fetal distress. In contrast, Ogundipe and associates (1994) randomly assigned 116 term pregnancies with an amnionic luid index < 5 cm to receive prophylactic amnioinfusion or standard obstetrical care. Overall cesarean delivery rates, delivery rates for fetal distress, or umbilical cord acid-base studies did not difer significantly between groups.
For meconium-stained amnionic luid, Pierce and associates (2000) reviewed 13 prospective trials of intrapartum amnioinfusion for 1924 women with meconium-stained fluid. In the amnioinfusion group, newborns were signiicantly less likely to have meconium below the vocal cords, and meconium aspiration syndrome rates were lower. he cesarean delivery rate was also reduced in the amnioinfusion group. Similar results were reported by Rathore and coworkers (2002).